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<!--Created on: 5/1/2019 10:35:37 AM-->
<!--Modified on: 5/1/2019 10:35:37 AM-->
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredRentReceivablesNet" xlink:to="us-gaap_DeferredRentReceivablesNet_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredRentReceivablesNet_lbl" xml:lang="en-US">Unbilled rents receivable, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherAssets" xlink:label="us-gaap_OtherAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssets" xlink:to="us-gaap_OtherAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherAssets_lbl" xml:lang="en-US">Other Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OtherAssets_lbl" xml:lang="en-US">Total deferred charges, goodwill and other assets, net</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsReceivableNet" xlink:label="us-gaap_AccountsReceivableNet" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsReceivableNet" xlink:to="us-gaap_AccountsReceivableNet_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccountsReceivableNet_lbl" xml:lang="en-US">Accounts Receivable Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AccountsReceivableNet_lbl" xml:lang="en-US">Accounts receivable, net of allowance for doubtful accounts of $602 and $1,108</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Assets_lbl" xml:lang="en-US">Total assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Assets_lbl" xml:lang="en-US">Total assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US">LIABILITIES AND EQUITY</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SeniorNotes" xlink:label="us-gaap_SeniorNotes" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SeniorNotes" xlink:to="us-gaap_SeniorNotes_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SeniorNotes_lbl" xml:lang="en-US">Senior Notes</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCredit" xlink:label="us-gaap_LineOfCredit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCredit" xlink:to="us-gaap_LineOfCredit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCredit_lbl" xml:lang="en-US">Revolving credit facility</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:label="us-gaap_LineOfCredit_lbl" xml:lang="en-US">Unsecured revolving credit facility and term loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCredit_lbl" xml:lang="en-US">Amount outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LineOfCredit_lbl" xml:lang="en-US">Outstanding borrowings under the facility</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SecuredDebt" xlink:label="us-gaap_SecuredDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SecuredDebt" xlink:to="us-gaap_SecuredDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SecuredDebt_lbl" xml:lang="en-US">Secured Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SecuredDebt_lbl" xml:lang="en-US">Mortgages, loans payable and other obligations, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:label="us-gaap_DividendsPayableCurrentAndNoncurrent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsPayableCurrentAndNoncurrent" xlink:to="us-gaap_DividendsPayableCurrentAndNoncurrent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendsPayableCurrentAndNoncurrent_lbl" xml:lang="en-US">Dividends and distributions payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:to="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_lbl" xml:lang="en-US">Accounts payable, accrued expenses and other liabilities</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RentsReceivedInAdvanceAndSecurityDeposits" xlink:label="cli_RentsReceivedInAdvanceAndSecurityDeposits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RentsReceivedInAdvanceAndSecurityDeposits" xlink:to="cli_RentsReceivedInAdvanceAndSecurityDeposits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RentsReceivedInAdvanceAndSecurityDeposits_lbl" xml:lang="en-US">Amount at the balance sheet date including both: (a) rents and other amounts paid in advance by tenants and clients; and (b) security deposits paid in advance to protect the provider of a service, such as a lessor, against damage or nonpayment by the tenant (lessee) during the term of the agreement.  Such damages may include physical damage to the property, theft of property, and other contractual breaches.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RentsReceivedInAdvanceAndSecurityDeposits_lbl" xml:lang="en-US">Rents received in advance and security deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPayableCurrentAndNoncurrent" xlink:to="us-gaap_InterestPayableCurrentAndNoncurrent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent_lbl" xml:lang="en-US">Accrued interest payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Liabilities" xlink:to="us-gaap_Liabilities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US">Total liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US">Total liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="us-gaap_CommitmentsAndContingencies" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsAndContingencies" xlink:to="us-gaap_CommitmentsAndContingencies_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommitmentsAndContingencies_lbl" xml:lang="en-US">Commitments And Contingencies 2009</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestEquityFairValue" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RedeemableNoncontrollingInterestEquityFairValue" xlink:to="us-gaap_RedeemableNoncontrollingInterestEquityFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityFairValue_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest, Equity, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityFairValue_lbl" xml:lang="en-US">Redeemable noncontrolling interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityFairValue_lbl" xml:lang="en-US">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RedeemableNoncontrollingInterestEquityFairValue_lbl" xml:lang="en-US">Redeemable noncontrolling interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterestAbstract_lbl" xml:lang="en-US">Equity:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityAbstract" xlink:to="us-gaap_StockholdersEquityAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US">Stockholders' Equity Attributable to Parent [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US">Mack-Cali Realty Corporation stockholders' equity:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockValue" xlink:label="us-gaap_CommonStockValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US">Common stock value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US">Common stock, $0.01 par value, 190,000,000 shares authorized, 90,325,783 and 90,320,306 shares outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapital" xlink:to="us-gaap_AdditionalPaidInCapital_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdditionalPaidInCapital_lbl" xml:lang="en-US">Additional Paid In Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdditionalPaidInCapital_lbl" xml:lang="en-US">Additional paid-in capital</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralPartnersCapitalAccount" xlink:label="us-gaap_GeneralPartnersCapitalAccount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralPartnersCapitalAccount" xlink:to="us-gaap_GeneralPartnersCapitalAccount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GeneralPartnersCapitalAccount_lbl" xml:lang="en-US">General Partners' Capital Account</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GeneralPartnersCapitalAccount_lbl" xml:lang="en-US">General Partner, 90,325,783 and 90,320,306 common units outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LimitedPartnersCapitalAccount" xlink:label="us-gaap_LimitedPartnersCapitalAccount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LimitedPartnersCapitalAccount" xlink:to="us-gaap_LimitedPartnersCapitalAccount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LimitedPartnersCapitalAccount_lbl" xml:lang="en-US">Limited Partners' Capital Account</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LimitedPartnersCapitalAccount_lbl" xml:lang="en-US">Limited partners, 10,009,355 and 10,229,349 common units/LTIPs outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsAccumulatedDeficit" xlink:to="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xml:lang="en-US">Retained Earnings Accumulated Deficit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RetainedEarningsAccumulatedDeficit_lbl" xml:lang="en-US">Dividends in excess of net earnings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xml:lang="en-US">Accumulated other comprehensive income (loss)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_StockholdersEquity_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US">Stockholders' Equity Attributable to Parent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US">Total Mack-Cali Realty Corporation stockholders' equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PartnersCapital" xlink:label="us-gaap_PartnersCapital" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PartnersCapital" xlink:to="us-gaap_PartnersCapital_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PartnersCapital_lbl" xml:lang="en-US">Partners' Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_PartnersCapital_lbl" xml:lang="en-US">Total Mack-Cali Realty, L.P. partners' capital</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestItemsAbstract" xlink:label="us-gaap_NoncontrollingInterestItemsAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncontrollingInterestItemsAbstract" xlink:to="us-gaap_NoncontrollingInterestItemsAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoncontrollingInterestItemsAbstract_lbl" xml:lang="en-US">Noncontrolling Interest Items [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NoncontrollingInterestItemsAbstract_lbl" xml:lang="en-US">Noncontrolling interests in subsidiaries:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestInOperatingPartnerships" xlink:label="us-gaap_MinorityInterestInOperatingPartnerships" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterestInOperatingPartnerships" xlink:to="us-gaap_MinorityInterestInOperatingPartnerships_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterestInOperatingPartnerships_lbl" xml:lang="en-US">Operating Partnership</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestInJointVentures" xlink:label="us-gaap_MinorityInterestInJointVentures" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterestInJointVentures" xlink:to="us-gaap_MinorityInterestInJointVentures_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterestInJointVentures_lbl" xml:lang="en-US">Minority Interest In Joint Ventures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MinorityInterestInJointVentures_lbl" xml:lang="en-US">Consolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterest" xlink:label="us-gaap_MinorityInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterest" xlink:to="us-gaap_MinorityInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterest_lbl" xml:lang="en-US">Total noncontrolling interests in subsidiaries</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_MinorityInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_MinorityInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_MinorityInterest_lbl" xml:lang="en-US">Total noncontrolling interests in subsidiaries</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_MinorityInterest_lbl" xml:lang="en-US">Noncontrolling interest's fair value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Total equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Total equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PartnersCapitalAttributableToNoncontrollingInterest" xlink:label="us-gaap_PartnersCapitalAttributableToNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PartnersCapitalAttributableToNoncontrollingInterest" xlink:to="us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Partners' Capital Attributable to Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PartnersCapitalAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Noncontrolling interests in consolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Partners' Capital, Including Portion Attributable to Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Balance, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_PartnersCapitalIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Total equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="us-gaap_LiabilitiesAndStockholdersEquity_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US">Liabilities And Stockholders Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US">Total liabilities and equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:to="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xml:lang="en-US">Allowance for doubtful accounts receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AllowanceForDoubtfulAccountsReceivable_lbl" xml:lang="en-US">Allowance for doubtful accounts receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockParOrStatedValuePerShare" xlink:to="us-gaap_CommonStockParOrStatedValuePerShare_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockParOrStatedValuePerShare_lbl" xml:lang="en-US">Common stock, par value per share</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="us-gaap_CommonStockSharesAuthorized" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesAuthorized" xlink:to="us-gaap_CommonStockSharesAuthorized_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockSharesAuthorized_lbl" xml:lang="en-US">Common stock, shares authorized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="us-gaap_CommonStockSharesOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockSharesOutstanding" xlink:to="us-gaap_CommonStockSharesOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xml:lang="en-US">Common Stock Shares Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockSharesOutstanding_lbl" xml:lang="en-US">Common stock, shares outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding" xlink:label="us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding" xlink:to="us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding_lbl" xml:lang="en-US">General Partners' Capital Account, Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GeneralPartnersCapitalAccountUnitsOutstanding_lbl" xml:lang="en-US">General partner common units outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding" xlink:label="us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding" xlink:to="us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_lbl" xml:lang="en-US">Limited Partners' Capital Account, Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LimitedPartnersCapitalAccountUnitsOutstanding_lbl" xml:lang="en-US">Limited partners common units outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementAbstract" xlink:label="us-gaap_IncomeStatementAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementAbstract" xlink:to="us-gaap_IncomeStatementAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementAbstract_lbl" xml:lang="en-US">Consolidated Statements Of Operations [Abstract]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenuesAbstract" xlink:label="us-gaap_RevenuesAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenuesAbstract" xlink:to="us-gaap_RevenuesAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RevenuesAbstract_lbl" xml:lang="en-US">Revenues Abstract</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RevenuesAbstract_lbl" xml:lang="en-US">REVENUES</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesIncomeStatementLeaseRevenue" xlink:label="us-gaap_OperatingLeasesIncomeStatementLeaseRevenue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesIncomeStatementLeaseRevenue" xlink:to="us-gaap_OperatingLeasesIncomeStatementLeaseRevenue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesIncomeStatementLeaseRevenue_lbl" xml:lang="en-US">Operating Leases, Income Statement, Lease Revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesIncomeStatementLeaseRevenue_lbl" xml:lang="en-US">Revenue from leases</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Revenues" xlink:label="us-gaap_Revenues" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Revenues" xlink:to="us-gaap_Revenues_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Revenues_lbl" xml:lang="en-US">Revenues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_Revenues_lbl" xml:lang="en-US">Total revenues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_Revenues_lbl" xml:lang="en-US">Total revenues</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfRevenueAbstract" xlink:label="us-gaap_CostOfRevenueAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfRevenueAbstract" xlink:to="us-gaap_CostOfRevenueAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CostOfRevenueAbstract_lbl" xml:lang="en-US">EXPENSES</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RealEstateTaxExpense" xlink:label="us-gaap_RealEstateTaxExpense" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateTaxExpense" xlink:to="us-gaap_RealEstateTaxExpense_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateTaxExpense_lbl" xml:lang="en-US">Real estate taxes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold" xlink:label="us-gaap_CostOfGoodsAndServicesSold" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CostOfGoodsAndServicesSold" xlink:to="us-gaap_CostOfGoodsAndServicesSold_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xml:lang="en-US">Construction and Development Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xml:lang="en-US">Costs of the project incurred</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_CostOfGoodsAndServicesSold_lbl" xml:lang="en-US">Utilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingCostsAndExpenses" xlink:label="us-gaap_OperatingCostsAndExpenses" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingCostsAndExpenses" xlink:to="us-gaap_OperatingCostsAndExpenses_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingCostsAndExpenses_lbl" xml:lang="en-US">Operating services</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CostsOfRealEstateServices" xlink:label="cli_CostsOfRealEstateServices" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CostsOfRealEstateServices" xlink:to="cli_CostsOfRealEstateServices_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CostsOfRealEstateServices_lbl" xml:lang="en-US">The aggregate costs including administrative paperwork, real estate brokerage, title, and property management operations.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CostsOfRealEstateServices_lbl" xml:lang="en-US">Costs Of Real Estate Services</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CostsOfRealEstateServices_lbl" xml:lang="en-US">Real estate services expenses</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LeasingPersonnelCosts" xlink:label="cli_LeasingPersonnelCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LeasingPersonnelCosts" xlink:to="cli_LeasingPersonnelCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LeasingPersonnelCosts_lbl" xml:lang="en-US">Leasing Personnel Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LeasingPersonnelCosts_lbl" xml:lang="en-US">Leasing Personnel Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LeasingPersonnelCosts_lbl" xml:lang="en-US">Leasing personnel costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="us-gaap_GeneralAndAdministrativeExpense" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_GainLossOnChangeOfControlOfInterests" xlink:to="cli_GainLossOnChangeOfControlOfInterests_lbl" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainLossOnSaleOfInvestments" xlink:to="us-gaap_GainLossOnSaleOfInvestments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainLossOnSaleOfInvestments_lbl" xml:lang="en-US">Gain (Loss) on Sale of Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_GainLossOnSaleOfInvestments_lbl" xml:lang="en-US">Gain on sale of investments in unconsolidated joint ventures</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ExtinguishmentOfDebtGainLossNetOfTax" xlink:to="us-gaap_ExtinguishmentOfDebtGainLossNetOfTax_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ExtinguishmentOfDebtGainLossNetOfTax_lbl" xml:lang="en-US">Extinguishment of Debt, Gain (Loss), Net of Tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ExtinguishmentOfDebtGainLossNetOfTax_lbl" xml:lang="en-US">Gain (loss) from extinguishment of debt, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ExtinguishmentOfDebtGainLossNetOfTax_lbl" xml:lang="en-US">Loss from extinguishment of debt, net</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NonoperatingIncomeExpenseIncludingEquityMethodInvestments" xlink:to="cli_NonoperatingIncomeExpenseIncludingEquityMethodInvestments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NonoperatingIncomeExpenseIncludingEquityMethodInvestments_lbl" xml:lang="en-US">Nonoperating Income Expense Including Equity Method Investments</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProfitLoss_lbl" xml:lang="en-US">Net income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ProfitLoss_lbl" xml:lang="en-US">Net income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProfitLoss_lbl" xml:lang="en-US">Net income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable_lbl" xml:lang="en-US">Add (deduct): Noncontrolling interests in consolidated joint ventures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossJointVenturePartnersNonredeemable_lbl" xml:lang="en-US">Noncontrolling interests in consolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable_lbl" xml:lang="en-US">Noncontrolling interest in operating partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable_lbl" xml:lang="en-US">Noncontrolling interests in Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable_lbl" xml:lang="en-US">Add (deduct): Noncontrolling interests in Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoncontrollingInterestInNetIncomeLossOperatingPartnershipsNonredeemable_lbl" xml:lang="en-US">Add (deduct): Noncontrolling interests in Operating Partnership</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest" xlink:label="us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_lbl" xml:lang="en-US">Net Income (Loss) Attributable to Redeemable Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_lbl" xml:lang="en-US">Redeemable noncontrolling interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest_lbl" xml:lang="en-US">Income Attributed to Noncontrolling Interests</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US">Net income (loss) available to common shareholders</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US">Net income available to common shareholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="us-gaap_EarningsPerShareBasicAbstract" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareBasicAbstract_lbl" xml:lang="en-US">Basic earnings per common share:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="us-gaap_EarningsPerShareBasic" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xml:lang="en-US">Earnings Per Share, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xml:lang="en-US">Net income available to common shareholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="us-gaap_EarningsPerShareDilutedAbstract" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareDilutedAbstract_lbl" xml:lang="en-US">Diluted earnings per common share:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="us-gaap_EarningsPerShareDiluted" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xml:lang="en-US">Earnings Per Share Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xml:lang="en-US">Net income available to common shareholders</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xml:lang="en-US">Net income (loss) available to common shareholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xml:lang="en-US">Basic weighted average shares outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xml:lang="en-US">Basic EPS shares</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders" xlink:to="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_lbl" xml:lang="en-US">Common unit distributions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_lbl" xml:lang="en-US">Common unit distributions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_lbl" xml:lang="en-US">Unit distributions</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment" xlink:label="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment" xlink:to="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest Redemption Value Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest Redemption Value Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment_lbl" xml:lang="en-US">Redemption Value Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_RedeemableNoncontrollingInterestRedemptionValueAdjustment_lbl" xml:lang="en-US">Redeemable noncontrolling interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestPeriodIncreaseDecrease" xlink:label="us-gaap_MinorityInterestPeriodIncreaseDecrease" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterestPeriodIncreaseDecrease" xlink:to="us-gaap_MinorityInterestPeriodIncreaseDecrease_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterestPeriodIncreaseDecrease_lbl" xml:lang="en-US">Noncontrolling Interest, Period Increase (Decrease)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MinorityInterestPeriodIncreaseDecrease_lbl" xml:lang="en-US">Change in noncontrolling interests in consolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MinorityInterestIncreaseDecreaseFromRedemptions" xlink:label="cli_MinorityInterestIncreaseDecreaseFromRedemptions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MinorityInterestIncreaseDecreaseFromRedemptions" xlink:to="cli_MinorityInterestIncreaseDecreaseFromRedemptions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MinorityInterestIncreaseDecreaseFromRedemptions_lbl" xml:lang="en-US">Minority Interest, Increase (Decrease) From Redemptions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MinorityInterestIncreaseDecreaseFromRedemptions_lbl" xml:lang="en-US">Minority Interest, Increase (Decrease) From Redemptions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MinorityInterestIncreaseDecreaseFromRedemptions_lbl" xml:lang="en-US">Redemption of common units for common stock, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_MinorityInterestIncreaseDecreaseFromRedemptions_lbl" xml:lang="en-US">Redemption of common units for common stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits" xlink:to="us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_lbl" xml:lang="en-US">Stock Issued During Period, Shares, Conversion of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesConversionOfUnits_lbl" xml:lang="en-US">Redemption of common units for common stock, shares</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested" xlink:label="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested" xlink:to="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested_lbl" xml:lang="en-US">Stock Issued During Period, Value, Long-Term Incentive Plan Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested_lbl" xml:lang="en-US">Stock Issued During Period, Value, Long-Term Incentive Plan Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_StockIssuedDuringPeriodValueLongTermIncentivePlanVested_lbl" xml:lang="en-US">Vested LTIP units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested" xlink:label="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested" xlink:to="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested_lbl" xml:lang="en-US">Stock Issued During Period, Shares, Long-Term Incentive Plan Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested_lbl" xml:lang="en-US">Stock Issued During Period, Shares, Long-Term Incentive Plan Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_StockIssuedDuringPeriodSharesLongTermIncentivePlanVested_lbl" xml:lang="en-US">Vested LTIP units, shares</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedemptionOfCommonUnits" xlink:label="cli_RedemptionOfCommonUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedemptionOfCommonUnits" xlink:to="cli_RedemptionOfCommonUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedemptionOfCommonUnits_lbl" xml:lang="en-US">Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedemptionOfCommonUnits_lbl" xml:lang="en-US">Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RedemptionOfCommonUnits_lbl" xml:lang="en-US">Redemption of common units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedemptionOfCommonUnitsShares" xlink:label="cli_RedemptionOfCommonUnitsShares" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedemptionOfCommonUnitsShares" xlink:to="cli_RedemptionOfCommonUnitsShares_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedemptionOfCommonUnitsShares_lbl" xml:lang="en-US">Redemption Of Common Units, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedemptionOfCommonUnitsShares_lbl" xml:lang="en-US">Redemption Of Common Units, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RedemptionOfCommonUnitsShares_lbl" xml:lang="en-US">Redemption of common units, shares</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings" xlink:to="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_lbl" xml:lang="en-US">Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_lbl" xml:lang="en-US">Shares issued under Dividend Reinvestment and Stock Purchase Plan, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_lbl" xml:lang="en-US">Shares issued under Dividend Reinvestment and Stock Purchase Plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockDividendsShares" xlink:label="us-gaap_StockDividendsShares" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockDividendsShares" xlink:to="us-gaap_StockDividendsShares_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockDividendsShares_lbl" xml:lang="en-US">Stock Dividends, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_StockDividendsShares_lbl" xml:lang="en-US">Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross" xlink:to="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_lbl" xml:lang="en-US">Stock Issued During Period, Value, Restricted Stock Award, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_lbl" xml:lang="en-US">Directors' deferred compensation plan, value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardGross_lbl" xml:lang="en-US">Directors' deferred compensation plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross" xlink:to="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_lbl" xml:lang="en-US">Stock Issued During Period, Shares, Restricted Stock Award, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross_lbl" xml:lang="en-US">Directors' deferred compensation plan, shares</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue" xlink:label="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue" xlink:to="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue_lbl" xml:lang="en-US">Adjustments To Additional Paid In Capital Sharebased Compensation Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue_lbl" xml:lang="en-US">Adjustments To Additional Paid In Capital Sharebased Compensation Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationValue_lbl" xml:lang="en-US">Stock compensation, value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xml:lang="en-US">Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_lbl" xml:lang="en-US">Stock compensation, shares</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited" xlink:to="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited_lbl" xml:lang="en-US">Stock Issued During Period, Value, Share-based Compensation, Forfeited</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationForfeited_lbl" xml:lang="en-US">Cancellation of unvested LTIP units, value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xml:lang="en-US">Cancellation of unvested LTIP units, shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_lbl" xml:lang="en-US">Shares forfeited and cancelled</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xml:lang="en-US">Other Comprehensive Income (Loss), Net of Tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherComprehensiveIncomeLossNetOfTax_lbl" xml:lang="en-US">Other comprehensive income (loss)</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance" xlink:label="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance" xlink:to="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance_lbl" xml:lang="en-US">Noncontrolling Interest, Increase (Decrease) from Subsidiary Equity Issuance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance_lbl" xml:lang="en-US">Noncontrolling Interest, Increase (Decrease) from Subsidiary Equity Issuance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NoncontrollingInterestIncreaseDecreaseFromSubsidiaryEquityIssuance_lbl" xml:lang="en-US">Rebalancing of ownership percentage between parent and subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="us-gaap_StatementOfCashFlowsAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xml:lang="en-US">Consolidated Statements Of Cash Flows [Abstract]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US">CASH FLOWS FROM OPERATING ACTIVITIES</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US">Adjustments to reconcile net income (loss) to net cash provided by Operating activities:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="us-gaap_DepreciationDepletionAndAmortization" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepreciationDepletionAndAmortization" xlink:to="us-gaap_DepreciationDepletionAndAmortization_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xml:lang="en-US">Depreciation and amortization, including related intangible assets</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AmortizationOfDeferredStockUnits" xlink:label="cli_AmortizationOfDeferredStockUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AmortizationOfDeferredStockUnits" xlink:to="cli_AmortizationOfDeferredStockUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AmortizationOfDeferredStockUnits_lbl" xml:lang="en-US">Amortization Of Deferred Stock Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AmortizationOfDeferredStockUnits_lbl" xml:lang="en-US">Amortization Of Deferred Stock Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AmortizationOfDeferredStockUnits_lbl" xml:lang="en-US">Amortization of directors deferred compensation stock units</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensation" xlink:to="us-gaap_ShareBasedCompensation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US">Stock compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US">Amortization of stock compensation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfFinancingCostsAndDiscounts" xlink:to="us-gaap_AmortizationOfFinancingCostsAndDiscounts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AmortizationOfFinancingCostsAndDiscounts_lbl" xml:lang="en-US">Amortization of deferred financing costs</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AmortizationOfDebtDiscountAndMarkToMarket" xlink:label="cli_AmortizationOfDebtDiscountAndMarkToMarket" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AmortizationOfDebtDiscountAndMarkToMarket" xlink:to="cli_AmortizationOfDebtDiscountAndMarkToMarket_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AmortizationOfDebtDiscountAndMarkToMarket_lbl" xml:lang="en-US">Amortization Of Debt Discount And Mark-To-Market</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AmortizationOfDebtDiscountAndMarkToMarket_lbl" xml:lang="en-US">Amortization Of Debt Discount And Mark-To-Market</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AmortizationOfDebtDiscountAndMarkToMarket_lbl" xml:lang="en-US">Amortization of debt discount and mark-to-market</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WriteOffOfDeferredDebtIssuanceCost" xlink:to="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xml:lang="en-US">Write off of Deferred Debt Issuance Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xml:lang="en-US">Write-off of unamortized deferred financing costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_WriteOffOfDeferredDebtIssuanceCost_lbl" xml:lang="en-US">Write off of unamortized deferred finance costs related to early extinguishment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:label="us-gaap_EquityMethodInvestmentDividendsOrDistributions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityMethodInvestmentDividendsOrDistributions" xlink:to="us-gaap_EquityMethodInvestmentDividendsOrDistributions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityMethodInvestmentDividendsOrDistributions_lbl" xml:lang="en-US">Equity Method Investment Dividends Or Distributions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_EquityMethodInvestmentDividendsOrDistributions_lbl" xml:lang="en-US">Distributions of cumulative earnings from unconsolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations" xlink:label="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations" xlink:to="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations_lbl" xml:lang="en-US">Realized Gains Loss On Disposition Of Assets, Including Discontinued Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations_lbl" xml:lang="en-US">Realized Gains Loss On Disposition Of Assets, Including Discontinued Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_RealizedGainsLossOnDispositionOfAssetsIncludingDiscontinuedOperations_lbl" xml:lang="en-US">Realized (gains) losses and unrealized losses on disposition of rental property, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:to="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xml:lang="en-US">Gains (Losses) on Extinguishment of Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xml:lang="en-US">(Gain)Loss from extinguishment of debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GainsLossesOnExtinguishmentOfDebt_lbl" xml:lang="en-US">Loss from extinguishment of debt, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:to="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_lbl" xml:lang="en-US">Changes in operating assets and liabilities:</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncreaseDecreaseInUnbilledRentReceivables" xlink:label="cli_IncreaseDecreaseInUnbilledRentReceivables" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncreaseDecreaseInUnbilledRentReceivables" xlink:to="cli_IncreaseDecreaseInUnbilledRentReceivables_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IncreaseDecreaseInUnbilledRentReceivables_lbl" xml:lang="en-US">Increase Decrease In Unbilled Rent Receivables</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncreaseDecreaseInUnbilledRentReceivables_lbl" xml:lang="en-US">Increase Decrease In Unbilled Rent Receivables</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_IncreaseDecreaseInUnbilledRentReceivables_lbl" xml:lang="en-US">Increase in unbilled rents receivable, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:to="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xml:lang="en-US">Increase in deferred charges and other assets, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncreaseDecreaseInOtherOperatingAssets_lbl" xml:lang="en-US">Increase in deferred charges, goodwill and other assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:label="us-gaap_IncreaseDecreaseInLeasingReceivables" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInLeasingReceivables" xlink:to="us-gaap_IncreaseDecreaseInLeasingReceivables_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInLeasingReceivables_lbl" xml:lang="en-US">(Increase) decrease in accounts receivable, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncreaseDecreaseInLeasingReceivables_lbl" xml:lang="en-US">Increase in accounts receivable, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities" xlink:to="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_lbl" xml:lang="en-US">Increase (decrease) in accounts payable, accrued expenses and other liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities_lbl" xml:lang="en-US">Increase in accounts payable, accrued expenses and other liabilities</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits" xlink:label="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits" xlink:to="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits_lbl" xml:lang="en-US">The net change during the reporting period in the amount at the balance sheet date including both: (a) rents and other amounts paid in advance by tenants and clients; and (b) security deposits paid in advance to protect the provider of a service, such as a lessor, against damage or nonpayment by the tenant (lessee) during the term of the agreement</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits_lbl" xml:lang="en-US">Increase Decrease In Rents Received In Advance And Security Deposits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_IncreaseDecreaseInRentsReceivedInAdvanceAndSecurityDeposits_lbl" xml:lang="en-US">Decrease in rents received in advance and security deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInInterestPayableNet" xlink:to="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xml:lang="en-US">Decrease in accrued interest payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInInterestPayableNet_lbl" xml:lang="en-US">Increase in accrued interest payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US">Net cash provided by operating activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US">Net cash provided by operating activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_lbl" xml:lang="en-US">CASH FLOWS FROM INVESTING ACTIVITIES</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:to="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US">Payments to Acquire Businesses, Net of Cash Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US">Rental property acquisitions and related intangibles</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireAndDevelopRealEstate" xlink:label="us-gaap_PaymentsToAcquireAndDevelopRealEstate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireAndDevelopRealEstate" xlink:to="us-gaap_PaymentsToAcquireAndDevelopRealEstate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireAndDevelopRealEstate_lbl" xml:lang="en-US">Payments to Acquire and Develop Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquireAndDevelopRealEstate_lbl" xml:lang="en-US">Rental property additions and improvements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PaymentsToAcquireAndDevelopRealEstate_lbl" xml:lang="en-US">Purchase price of property</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToDevelopRealEstateAssets" xlink:label="us-gaap_PaymentsToDevelopRealEstateAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToDevelopRealEstateAssets" xlink:to="us-gaap_PaymentsToDevelopRealEstateAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToDevelopRealEstateAssets_lbl" xml:lang="en-US">Payments to Develop Real Estate Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToDevelopRealEstateAssets_lbl" xml:lang="en-US">Development of rental property and other related costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromSaleOfBuildings" xlink:label="us-gaap_ProceedsFromSaleOfBuildings" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfBuildings" xlink:to="us-gaap_ProceedsFromSaleOfBuildings_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfBuildings_lbl" xml:lang="en-US">Net Sales Proceeds</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromSaleOfBuildings_lbl" xml:lang="en-US">Proceeds from the sales of rental property</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromDivestitureOfInterestInJointVenture" xlink:label="us-gaap_ProceedsFromDivestitureOfInterestInJointVenture" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromDivestitureOfInterestInJointVenture_lbl" xml:lang="en-US">Proceeds from the sale of investments in unconsolidated joint ventures</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromCollectionOfLoansReceivable" xlink:to="us-gaap_ProceedsFromCollectionOfLoansReceivable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromCollectionOfLoansReceivable_lbl" xml:lang="en-US">Proceeds from Collection of Loans Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromCollectionOfLoansReceivable_lbl" xml:lang="en-US">Repayment of notes receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:label="us-gaap_PaymentsToAcquireInterestInJointVenture" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireInterestInJointVenture" xlink:to="us-gaap_PaymentsToAcquireInterestInJointVenture_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireInterestInJointVenture_lbl" xml:lang="en-US">Investment in unconsolidated joint ventures</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DistributionsInExcessOfCumulativeEarningsFromJvs_lbl" xml:lang="en-US">This item represents the amount of distributions in excess of net earnings, which represents a return of investment, received from unconsolidated joint ventures and subsidiaries; these investments are accounted for under the equity method of accounting.</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US">Net cash used in investing activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US">Net cash provided by investing activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_lbl" xml:lang="en-US">CASH FLOW FROM FINANCING ACTIVITIES</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromUnsecuredLinesOfCredit" xlink:to="us-gaap_ProceedsFromUnsecuredLinesOfCredit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromUnsecuredLinesOfCredit_lbl" xml:lang="en-US">Borrowings from revolving credit facility</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfLinesOfCredit" xlink:label="us-gaap_RepaymentsOfLinesOfCredit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfLinesOfCredit" xlink:to="us-gaap_RepaymentsOfLinesOfCredit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RepaymentsOfLinesOfCredit_lbl" xml:lang="en-US">Repayment of revolving credit facility and money market loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_RepaymentsOfLinesOfCredit_lbl" xml:lang="en-US">Repayment of revolving credit facility</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RepaymentsOfLinesOfCredit_lbl" xml:lang="en-US">Payment for borrowings</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromUnsecuredTermLoan" xlink:label="cli_ProceedsFromUnsecuredTermLoan" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromUnsecuredTermLoan" xlink:to="cli_ProceedsFromUnsecuredTermLoan_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromUnsecuredTermLoan_lbl" xml:lang="en-US">Proceeds From Unsecured Term Loan</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromUnsecuredTermLoan_lbl" xml:lang="en-US">Proceeds From Unsecured Term Loan</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromUnsecuredTermLoan_lbl" xml:lang="en-US">Repayment of unsecured term loan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfSecuredDebt" xlink:to="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xml:lang="en-US">Proceeds from Issuance of Secured Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfSecuredDebt_lbl" xml:lang="en-US">Proceeds from mortgages and loans payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RepaymentsOfSecuredDebt" xlink:label="us-gaap_RepaymentsOfSecuredDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfSecuredDebt" xlink:to="us-gaap_RepaymentsOfSecuredDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RepaymentsOfSecuredDebt_lbl" xml:lang="en-US">Repayment of mortgages, loans payable and other obligations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_RepaymentsOfSecuredDebt_lbl" xml:lang="en-US">Repayment of mortgages, loans payable and other obligations</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsToAcquireMinorityInterest" xlink:label="cli_PaymentsToAcquireMinorityInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsToAcquireMinorityInterest" xlink:to="cli_PaymentsToAcquireMinorityInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsToAcquireMinorityInterest_lbl" xml:lang="en-US">Payments To Acquire Minority Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsToAcquireMinorityInterest_lbl" xml:lang="en-US">Payments To Acquire Minority Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_PaymentsToAcquireMinorityInterest_lbl" xml:lang="en-US">Acquisition of noncontrolling interests</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests" xlink:label="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests" xlink:to="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests_lbl" xml:lang="en-US">Proceeds From Issuance Of Redeemable Noncontrolling Interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests_lbl" xml:lang="en-US">Proceeds From Issuance Of Redeemable Noncontrolling Interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromIssuanceOfRedeemableNoncontrollingInterests_lbl" xml:lang="en-US">Issuance of redeemable noncontrolling interests, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfFinancingCosts" xlink:label="us-gaap_PaymentsOfFinancingCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfFinancingCosts" xlink:to="us-gaap_PaymentsOfFinancingCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsOfFinancingCosts_lbl" xml:lang="en-US">Payment of financing costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsOfFinancingCosts_lbl" xml:lang="en-US">Payment of financing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromPaymentsToMinorityShareholders" xlink:label="us-gaap_ProceedsFromPaymentsToMinorityShareholders" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromPaymentsToMinorityShareholders" xlink:to="us-gaap_ProceedsFromPaymentsToMinorityShareholders_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromPaymentsToMinorityShareholders_lbl" xml:lang="en-US">Proceeds from (Payments to) Noncontrolling Interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromPaymentsToMinorityShareholders_lbl" xml:lang="en-US">Distributions to noncontrolling interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsOfCapitalDistribution" xlink:label="us-gaap_PaymentsOfCapitalDistribution" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfCapitalDistribution" xlink:to="us-gaap_PaymentsOfCapitalDistribution_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsOfCapitalDistribution_lbl" xml:lang="en-US">Payment of dividends and distributions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsOfCapitalDistribution_lbl" xml:lang="en-US">Payment of dividends and distributions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xml:lang="en-US">Net cash provided used in financing activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities_lbl" xml:lang="en-US">Net cash used in financing activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_lbl" xml:lang="en-US">Net (decrease) increase in cash and cash equivalents</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect_lbl" xml:lang="en-US">Net decrease in cash and cash equivalents</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xml:lang="en-US">Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xml:lang="en-US">Cash, cash equivalents and restricted cash, end of period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_lbl" xml:lang="en-US">Cash, cash equivalents and restricted cash, beginning of period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract" xlink:to="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_lbl" xml:lang="en-US">Organization And Basis Of Presentation [Abstract]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OrganizationAndBasisOfPresentationTable" xlink:label="cli_OrganizationAndBasisOfPresentationTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OrganizationAndBasisOfPresentationTable" xlink:to="cli_OrganizationAndBasisOfPresentationTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OrganizationAndBasisOfPresentationTable_lbl" xml:lang="en-US">Organization And Basis Of Presentation [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OrganizationAndBasisOfPresentationTable_lbl" xml:lang="en-US">Organization And Basis Of Presentation [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OrganizationAndBasisOfPresentationLineItems" xlink:label="cli_OrganizationAndBasisOfPresentationLineItems" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OrganizationAndBasisOfPresentationLineItems_lbl" xml:lang="en-US">Organization And Basis Of Presentation [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OrganizationAndBasisOfPresentationLineItems_lbl" xml:lang="en-US">Organization And Basis Of Presentation [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock_lbl" xml:lang="en-US">Organization Consolidation And Presentation Of Financial Statements Disclosure TextBlock</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SignificantAccountingPoliciesTable_lbl" xml:lang="en-US">Significant Accounting Policies [Table]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SignificantAccountingPoliciesLineItems_lbl" xml:lang="en-US">Significant Accounting Policies [Line Items]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RecentTransactionsAbstract" xlink:to="cli_RecentTransactionsAbstract_lbl" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RecentTransactionsAbstract_lbl" xml:lang="en-US">Recent Transactions [Abstract]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RecentTransactionsTable" xlink:to="cli_RecentTransactionsTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RecentTransactionsTable_lbl" xml:lang="en-US">Recent Transactions [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RecentTransactionsTable_lbl" xml:lang="en-US">Recent Transactions [Table]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RecentTransactionsLineItems" xlink:to="cli_RecentTransactionsLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RecentTransactionsLineItems_lbl" xml:lang="en-US">Recent Transactions [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RecentTransactionsLineItems_lbl" xml:lang="en-US">Recent Transactions [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RecentTransactionsTextBlock" xlink:label="cli_RecentTransactionsTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RecentTransactionsTextBlock" xlink:to="cli_RecentTransactionsTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RecentTransactionsTextBlock_lbl" xml:lang="en-US">Recent Transactions [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RecentTransactionsTextBlock_lbl" xml:lang="en-US">Recent Transactions [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RecentTransactionsTextBlock_lbl" xml:lang="en-US">Recent Transactions</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityMethodInvestmentsAndJointVenturesAbstract_lbl" xml:lang="en-US">Investments In Unconsolidated Joint Ventures [Abstract]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InvestmentsInUnconsolidatedJointVenturesTable" xlink:label="cli_InvestmentsInUnconsolidatedJointVenturesTable" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InvestmentsInUnconsolidatedJointVenturesTable_lbl" xml:lang="en-US">Investments In Unconsolidated Joint Ventures [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InvestmentsInUnconsolidatedJointVenturesLineItems" xlink:label="cli_InvestmentsInUnconsolidatedJointVenturesLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InvestmentsInUnconsolidatedJointVenturesLineItems" xlink:to="cli_InvestmentsInUnconsolidatedJointVenturesLineItems_lbl" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InvestmentsInUnconsolidatedJointVenturesLineItems_lbl" xml:lang="en-US">Investments In Unconsolidated Joint Ventures [Line Items]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityMethodInvestmentsDisclosureTextBlock_lbl" xml:lang="en-US">Equity Method Investments Disclosure TextBlock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_EquityMethodInvestmentsDisclosureTextBlock_lbl" xml:lang="en-US">Investments In Unconsolidated Joint Ventures</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssetsAbstract" xlink:to="us-gaap_OtherAssetsAbstract_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherAssetsAbstract_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets, Net [Abstract]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredChargesGoodwillAndOtherAssetsTable" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredChargesGoodwillAndOtherAssetsTable" xlink:to="cli_DeferredChargesGoodwillAndOtherAssetsTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsTable_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsTable_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredChargesGoodwillAndOtherAssetsLineItems" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsLineItems" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsLineItems_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock" xlink:label="us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureTextBlock" />
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    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RestrictedCashTable" xlink:label="cli_RestrictedCashTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RestrictedCashTable" xlink:to="cli_RestrictedCashTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RestrictedCashTable_lbl" xml:lang="en-US">Restricted Cash [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RestrictedCashTable_lbl" xml:lang="en-US">Restricted Cash [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RestrictedCashLineItems" xlink:label="cli_RestrictedCashLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RestrictedCashLineItems" xlink:to="cli_RestrictedCashLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RestrictedCashLineItems_lbl" xml:lang="en-US">Restricted Cash [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RestrictedCashLineItems_lbl" xml:lang="en-US">Restricted Cash [Line Items]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RestrictedAssetsDisclosureTextBlock_lbl" xml:lang="en-US">Restricted Cash</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtDisclosureTable_lbl" xml:lang="en-US">Debt Disclosure [Table]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtDisclosureLineItems_lbl" xml:lang="en-US">Debt Disclosure [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtDisclosureLineItems_lbl" xml:lang="en-US">Debt Disclosure [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SeniorUnsecuredNotesTextBlock" xlink:label="cli_SeniorUnsecuredNotesTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SeniorUnsecuredNotesTextBlock_lbl" xml:lang="en-US">Senior Unsecured Notes [Text Block]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CompensationAndRetirementDisclosureTable_lbl" xml:lang="en-US">Compensation And Retirement Disclosure [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CompensationAndRetirementDisclosureLineItems" xlink:label="cli_CompensationAndRetirementDisclosureLineItems" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US">Property, Plant and Equipment, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US">Rental Property</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RealEstateHeldForDevelopmentAndSalePolicy" xlink:label="us-gaap_RealEstateHeldForDevelopmentAndSalePolicy" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateHeldForDevelopmentAndSalePolicy" xlink:to="us-gaap_RealEstateHeldForDevelopmentAndSalePolicy_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateHeldForDevelopmentAndSalePolicy_lbl" xml:lang="en-US">Real Estate Held for Development and Sale, Policy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_RealEstateHeldForDevelopmentAndSalePolicy_lbl" xml:lang="en-US">Rental Property Held For Sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityMethodInvestmentsPolicy" xlink:label="us-gaap_EquityMethodInvestmentsPolicy" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityMethodInvestmentsPolicy" xlink:to="us-gaap_EquityMethodInvestmentsPolicy_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityMethodInvestmentsPolicy_lbl" xml:lang="en-US">Equity Method Investments, Policy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_EquityMethodInvestmentsPolicy_lbl" xml:lang="en-US">Investments In Unconsolidated Joint Ventures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsPolicyTextBlock" xlink:to="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xml:lang="en-US">Cash and Cash Equivalents, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xml:lang="en-US">Cash And Cash Equivalents</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredFinancingCostsPolicyTextBlock" xlink:label="cli_DeferredFinancingCostsPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredFinancingCostsPolicyTextBlock" xlink:to="cli_DeferredFinancingCostsPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredFinancingCostsPolicyTextBlock_lbl" xml:lang="en-US">Disclosure of entity's accounting policy for costs incurred in connection with obtaining finance.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredFinancingCostsPolicyTextBlock_lbl" xml:lang="en-US">Deferred Financing Costs Policy Text Block</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DeferredFinancingCostsPolicyTextBlock_lbl" xml:lang="en-US">Deferred Financing Costs</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredLeasingCostsPolicyTextBlock" xlink:label="cli_DeferredLeasingCostsPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredLeasingCostsPolicyTextBlock" xlink:to="cli_DeferredLeasingCostsPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredLeasingCostsPolicyTextBlock_lbl" xml:lang="en-US">Disclosure of the entity's accounting policy for costs incurred in connection with leases.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredLeasingCostsPolicyTextBlock_lbl" xml:lang="en-US">Deferred Leasing Costs Policy Text Block</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DeferredLeasingCostsPolicyTextBlock_lbl" xml:lang="en-US">Deferred Leasing Costs/Leasing Personnel Costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:label="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:to="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_lbl" xml:lang="en-US">Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_lbl" xml:lang="en-US">Goodwill</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativesPolicyTextBlock" xlink:label="us-gaap_DerivativesPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativesPolicyTextBlock" xlink:to="us-gaap_DerivativesPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xml:lang="en-US">Derivatives, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xml:lang="en-US">Derivative Instruments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RevenueRecognitionPolicyTextBlock" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueRecognitionPolicyTextBlock" xlink:to="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xml:lang="en-US">Revenue Recognition, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RevenueRecognitionPolicyTextBlock_lbl" xml:lang="en-US">Revenue Recognition</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock" xlink:label="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock" xlink:to="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock_lbl" xml:lang="en-US">Allowance For Doubtful Accounts Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock_lbl" xml:lang="en-US">Allowance For Doubtful Accounts Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AllowanceForDoubtfulAccountsPolicyPolicyTextBlock_lbl" xml:lang="en-US">Allowance For Doubtful Accounts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="us-gaap_IncomeTaxPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxPolicyTextBlock" xlink:to="us-gaap_IncomeTaxPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xml:lang="en-US">Income Tax, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xml:lang="en-US">Income And Other Taxes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="us-gaap_EarningsPerSharePolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xml:lang="en-US">Earnings Per Share, Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xml:lang="en-US">Earnings Per Share Or Unit</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DividendsAndDistributionsPayablePolicyTextBlock" xlink:label="cli_DividendsAndDistributionsPayablePolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DividendsAndDistributionsPayablePolicyTextBlock" xlink:to="cli_DividendsAndDistributionsPayablePolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DividendsAndDistributionsPayablePolicyTextBlock_lbl" xml:lang="en-US">Disclosure of the entity's accounting policy for declaring and paying dividends and distributions.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DividendsAndDistributionsPayablePolicyTextBlock_lbl" xml:lang="en-US">Dividends And Distributions Payable Policy Text Block</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DividendsAndDistributionsPayablePolicyTextBlock_lbl" xml:lang="en-US">Dividends And Distributions Payable</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IssuanceCostsPolicyTextBlock" xlink:label="cli_IssuanceCostsPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IssuanceCostsPolicyTextBlock" xlink:to="cli_IssuanceCostsPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IssuanceCostsPolicyTextBlock_lbl" xml:lang="en-US">Disclosure of the accounting policy for costs incurred in connection with stock issuances.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IssuanceCostsPolicyTextBlock_lbl" xml:lang="en-US">Issuance Costs Policy Text Block</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_IssuanceCostsPolicyTextBlock_lbl" xml:lang="en-US">Costs Incurred For Stock Issuances</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US">Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US">Stock Compensation</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OtherComprehensiveIncomePolicyTextBlock" xlink:label="cli_OtherComprehensiveIncomePolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OtherComprehensiveIncomePolicyTextBlock" xlink:to="cli_OtherComprehensiveIncomePolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OtherComprehensiveIncomePolicyTextBlock_lbl" xml:lang="en-US">Other Comprehensive Income Policy [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OtherComprehensiveIncomePolicyTextBlock_lbl" xml:lang="en-US">Other Comprehensive Income Policy Text Block</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_OtherComprehensiveIncomePolicyTextBlock_lbl" xml:lang="en-US">Other Comprehensive Income (Loss)</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedeemableNoncontrollingInterestsPolicyTextBlock" xlink:label="cli_RedeemableNoncontrollingInterestsPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedeemableNoncontrollingInterestsPolicyTextBlock" xlink:to="cli_RedeemableNoncontrollingInterestsPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedeemableNoncontrollingInterestsPolicyTextBlock_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedeemableNoncontrollingInterestsPolicyTextBlock_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RedeemableNoncontrollingInterestsPolicyTextBlock_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementPolicyPolicyTextBlock" xlink:to="us-gaap_FairValueMeasurementPolicyPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock_lbl" xml:lang="en-US">Fair Value Measurement, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementPolicyPolicyTextBlock_lbl" xml:lang="en-US">Fair Value Hierarchy</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US">Impact Of Recently-Issued Accounting Standards</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock" xlink:label="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock" xlink:to="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock_lbl" xml:lang="en-US">Schedule Of Rental Property Improvements, Not In Service [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock_lbl" xml:lang="en-US">Schedule Of Rental Property Improvements, Not In Service [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfRentalPropertyImprovementsNotInServiceTextBlock_lbl" xml:lang="en-US">Schedule Of Rental Property Improvements</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock" xlink:label="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock" xlink:to="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock_lbl" xml:lang="en-US">Schedule of Estimated Useful Lives of Assets [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock_lbl" xml:lang="en-US">Schedule of Estimated Useful Lives of Assets [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfEstimatedUsefulLivesOfAssetsTextBlock_lbl" xml:lang="en-US">Estimated Useful Lives Of Assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:label="us-gaap_ScheduleOfRealEstatePropertiesTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:to="us-gaap_ScheduleOfRealEstatePropertiesTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfRealEstatePropertiesTable_lbl" xml:lang="en-US">Schedule of Real Estate Properties [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RealEstatePropertiesLineItems" xlink:label="us-gaap_RealEstatePropertiesLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstatePropertiesLineItems" xlink:to="us-gaap_RealEstatePropertiesLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstatePropertiesLineItems_lbl" xml:lang="en-US">Real Estate Properties [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock_lbl" xml:lang="en-US">Schedule of Business Acquisitions, by Acquisition [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTextBlock_lbl" xml:lang="en-US">Schedule Of Properties Acquired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:label="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:to="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_lbl" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfOtherAssetsTableTextBlock" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock_lbl" xml:lang="en-US">Schedule of Other Assets [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfOtherAssetsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Deferred Charges, Goodwill And Other Assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xml:lang="en-US">Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfDerivativeInstrumentsInStatementOfFinancialPositionFairValueTextBlock_lbl" xml:lang="en-US">Schedule Of Fair Value Of The Derivative Financial Instruments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfCashFlowHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock" xlink:label="us-gaap_ScheduleOfCashFlowHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfCashFlowHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock_lbl" xml:lang="en-US">Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfCashFlowHedgingInstrumentsStatementsOfFinancialPerformanceAndFinancialPositionLocationTableTextBlock_lbl" xml:lang="en-US">Schedule Of Cash Flow Hedging, Derivative Financial Instruments On The Income Statement</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" xlink:label="us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock_lbl" xml:lang="en-US">Schedule of Restricted Cash and Cash Equivalents [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfRestrictedCashAndCashEquivalentsTextBlock_lbl" xml:lang="en-US">Schedule Of Restricted Cash</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="us-gaap_DebtInstrumentTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentTable_lbl" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US">Debt Instrument [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:to="us-gaap_ScheduleOfDebtInstrumentsTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock_lbl" xml:lang="en-US">Schedule of Senior Unsecured Notes [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock_lbl" xml:lang="en-US">Summary Of Senior Unsecured Notes</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock" xlink:label="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock" xlink:to="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans And Facility Fee [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans And Facility Fee [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfDefinedLeverageRatioIncludingInterestRateAlternateBaseRateLoansAndFacilityFeeTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans, And Facility Fee</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfUnsecuredCreditRatingAlternateBaseRateLoansAndCreditFacilityFeeOperatingPartnershipsTableTextBlock" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAlternateBaseRateLoansAndCreditFacilityFeeOperatingPartnershipsTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAlternateBaseRateLoansAndCreditFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating, Alternate Base Rate Loans And Credit Facility Fee, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAlternateBaseRateLoansAndCreditFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating, Alternate Base Rate Loans And Credit Facility Fee, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAlternateBaseRateLoansAndCreditFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Interest Rates On Outstanding Borrowings, Alternate Base Rate Loans, And Facility Fee</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfUnsecuredCreditRatingAndFacilityFeeOperatingPartnershipsTableTextBlock" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAndFacilityFeeOperatingPartnershipsTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAndFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating And Facility Fee, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAndFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating And Facility Fee, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfUnsecuredCreditRatingAndFacilityFeeOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating And Facility Fee</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfDefinedLeverageRatioTableTextBlock" xlink:label="cli_ScheduleOfDefinedLeverageRatioTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfDefinedLeverageRatioTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfDefinedLeverageRatioTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfDefinedLeverageRatioTableTextBlock_lbl" xml:lang="en-US">Schedule Of Defined Leverage Ratio</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock" xlink:label="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock" xlink:to="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Unsecured Credit Rating, Operating Partnerships [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_ScheduleOfUnsecuredCreditRatingOperatingPartnershipsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Interest Rate On Outstanding Borrowings Payable</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfSecuredDebtTableTextBlock" xlink:label="cli_ScheduleOfSecuredDebtTableTextBlock" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfSecuredDebtTableTextBlock_lbl" xml:lang="en-US">Schedule of Secured Debt [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfSecuredDebtTableTextBlock_lbl" xml:lang="en-US">Schedule of Secured Debt [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfSecuredDebtTableTextBlock_lbl" xml:lang="en-US">Summary Of Mortgages, Loans Payable And Other Obligations</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommitmentsAndContingenciesDisclosureTable" xlink:label="cli_CommitmentsAndContingenciesDisclosureTable" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommitmentsAndContingenciesDisclosureTable_lbl" xml:lang="en-US">Commitments And Contingencies Disclosure [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommitmentsAndContingenciesDisclosureTable_lbl" xml:lang="en-US">Commitments And Contingencies Disclosure [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommitmentsAndContingenciesDisclosureLineItems" xlink:label="cli_CommitmentsAndContingenciesDisclosureLineItems" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommitmentsAndContingenciesDisclosureLineItems_lbl" xml:lang="en-US">Commitments And Contingencies Disclosure [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommitmentsAndContingenciesDisclosureLineItems_lbl" xml:lang="en-US">Commitments And Contingencies Disclosure [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock" xlink:to="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_lbl" xml:lang="en-US">Schedule Of Future Minimum Rental Payments For Operating Leases [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ScheduleOfFutureMinimumRentalPaymentsForOperatingLeasesTableTextBlock_lbl" xml:lang="en-US">Future Minimum Rental Payments Of Ground Leases</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock" xlink:label="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock" xlink:to="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock_lbl" xml:lang="en-US">Schedule Of Future Minimum Rentals Under Non-cancelable Operating Lease [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock_lbl" xml:lang="en-US">Schedule Of Future Minimum Rentals Under Non-cancelable Operating Lease [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ScheduleOfFutureMinimumRentalsUnderNonCancelableOperatingLeaseTextBlock_lbl" xml:lang="en-US">Future Minimum Rentals To Be Received Under Non-Cancelable Operating Leases</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RedeemableNoncontrollingInterestTableTextBlock" xlink:label="us-gaap_RedeemableNoncontrollingInterestTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RedeemableNoncontrollingInterestTableTextBlock" xlink:to="us-gaap_RedeemableNoncontrollingInterestTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RedeemableNoncontrollingInterestTableTextBlock_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RedeemableNoncontrollingInterestTableTextBlock_lbl" xml:lang="en-US">Schedule Of Changes In The Value Of The Redeemable Noncontrolling Interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfStockholdersEquityTableTextBlock" xlink:label="us-gaap_ScheduleOfStockholdersEquityTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfStockholdersEquityTableTextBlock" xlink:to="us-gaap_ScheduleOfStockholdersEquityTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfStockholdersEquityTableTextBlock_lbl" xml:lang="en-US">Schedule of Stockholders Equity [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfStockholdersEquityTableTextBlock_lbl" xml:lang="en-US">Schedule Of General Partner Capital</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock" xlink:to="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xml:lang="en-US">Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_lbl" xml:lang="en-US">Schedule Of Stock Option Plans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock" xlink:to="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xml:lang="en-US">Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_lbl" xml:lang="en-US">Schedule Of Weighted Average Assumptions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:label="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:to="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_lbl" xml:lang="en-US">Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_lbl" xml:lang="en-US">Schedule Of Restricted Stock Awards</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:to="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_lbl" xml:lang="en-US">Schedule Of Reconciliation Of Shares Used In Basic EPS Calculation To Shares Used In Diluted EPS Calculation</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MinorityInterestTableTextBlock" xlink:label="cli_MinorityInterestTableTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MinorityInterestTableTextBlock" xlink:to="cli_MinorityInterestTableTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MinorityInterestTableTextBlock_lbl" xml:lang="en-US">Minority Interest [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MinorityInterestTableTextBlock_lbl" xml:lang="en-US">Minority Interest [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MinorityInterestTableTextBlock_lbl" xml:lang="en-US">Schedule Of Activity Of Noncontrolling Interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock" xlink:label="us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock" xlink:to="us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock_lbl" xml:lang="en-US">Schedule of Other Ownership Interests [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfOtherOwnershipInterestsTextBlock_lbl" xml:lang="en-US">Changes In Noncontrolling Interests Of Subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_lbl" xml:lang="en-US">Schedule Of Selected Results Of Operations And Asset Information</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock" xlink:label="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock" xlink:to="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock_lbl" xml:lang="en-US">Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ReconciliationOfOperatingProfitLossFromSegmentsToConsolidatedTextBlock_lbl" xml:lang="en-US">Schedule Of Reconciliation Of Net Operating Income To Net Income Available To Common Shareholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:label="srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis" xlink:to="srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_lbl" xml:lang="en-US">Real Estate, Type of Property [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:label="srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MortgageLoansOnRealEstateNamePropertyTypeDomain" xlink:to="srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_lbl" xml:lang="en-US">Mortgage Loans On Real Estate Name Property Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_lbl" xml:lang="en-US">Real Estate [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureOfficeBuildingsMember" xlink:label="cli_UnconsolidatedJointVentureOfficeBuildingsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureOfficeBuildingsMember" xlink:to="cli_UnconsolidatedJointVentureOfficeBuildingsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureOfficeBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureOfficeBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureOfficeBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office Buildings [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MultipleFamilyPropertiesMember" xlink:label="cli_MultipleFamilyPropertiesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MultipleFamilyPropertiesMember" xlink:to="cli_MultipleFamilyPropertiesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Multi-Family Properties [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Multiple Family Properties [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Multi-Family Properties [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember" xlink:label="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember" xlink:to="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Multiple Family Properties [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Multiple Family Properties [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureMultipleFamilyPropertiesMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Multi-Family Properties [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember" xlink:label="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember" xlink:to="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office/Flex Buildings And Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office Flex Buildings And Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureOfficeFlexBuildingsAndHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Office/Flex Buildings And Hotel [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ParkingRetailMember" xlink:label="cli_ParkingRetailMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ParkingRetailMember" xlink:to="cli_ParkingRetailMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ParkingRetailMember_lbl" xml:lang="en-US">Parking/Retail [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ParkingRetailMember_lbl" xml:lang="en-US">Parking Retail [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ParkingRetailMember_lbl" xml:lang="en-US">Parking/Retail [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureParkingRetailBuildingsMember" xlink:label="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember" xlink:to="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Parking/Retail Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Parking Retail Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureParkingRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Parking/Retail Buildings [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandMember" xlink:label="us-gaap_LandMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandMember" xlink:to="us-gaap_LandMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LandMember_lbl" xml:lang="en-US">Land [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LandMember_lbl" xml:lang="en-US">Land [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_GeneralPartnerOwnershipPercentage" xlink:label="cli_GeneralPartnerOwnershipPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_GeneralPartnerOwnershipPercentage" xlink:to="cli_GeneralPartnerOwnershipPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_GeneralPartnerOwnershipPercentage_lbl" xml:lang="en-US">General Partner Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_GeneralPartnerOwnershipPercentage_lbl" xml:lang="en-US">General Partner Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_GeneralPartnerOwnershipPercentage_lbl" xml:lang="en-US">Percentage of ownership interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RealEstatePropertyOwnedAndInvestmentInterest" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealEstatePropertyOwnedAndInvestmentInterest" xlink:to="cli_RealEstatePropertyOwnedAndInvestmentInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterest_lbl" xml:lang="en-US">Real Estate Property Owned and Investment Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterest_lbl" xml:lang="en-US">Real Estate Property Owned and Investment Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterest_lbl" xml:lang="en-US">Number of properties owned or investment interests</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RealEstatePropertyOwnedAndInvestmentInterestArea" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterestArea" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealEstatePropertyOwnedAndInvestmentInterestArea" xlink:to="cli_RealEstatePropertyOwnedAndInvestmentInterestArea_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterestArea_lbl" xml:lang="en-US">Real Estate Property Owned and Investment Interest, Area</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterestArea_lbl" xml:lang="en-US">Real Estate Property Owned and Investment Interest, Area</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RealEstatePropertyOwnedAndInvestmentInterestArea_lbl" xml:lang="en-US">Aggregate square feet of the property owned or investment interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfTenants" xlink:label="cli_NumberOfTenants" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfTenants" xlink:to="cli_NumberOfTenants_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfTenants_lbl" xml:lang="en-US">Number Of Tenants</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfTenants_lbl" xml:lang="en-US">Number Of Tenants</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfTenants_lbl" xml:lang="en-US">Number of tenants</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfUnitsInRealEstateProperty" xlink:label="us-gaap_NumberOfUnitsInRealEstateProperty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfUnitsInRealEstateProperty" xlink:to="us-gaap_NumberOfUnitsInRealEstateProperty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NumberOfUnitsInRealEstateProperty_lbl" xml:lang="en-US">Number Of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NumberOfUnitsInRealEstateProperty_lbl" xml:lang="en-US">Number of Apartment Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NumberOfUnitsInRealEstateProperty_lbl" xml:lang="en-US">Number of units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation" xlink:label="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation" xlink:to="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation_lbl" xml:lang="en-US">Real Estate Property Owned or Investment Interest, Number of Location</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation_lbl" xml:lang="en-US">Real Estate Property Owned or Investment Interest, Number of Location</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_RealEstatePropertyOwnedOrInvestmentInterestNumberOfLocation_lbl" xml:lang="en-US">Number of states where properties are located</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ConsolidatedJointVenturesRealEstateAssets" xlink:label="cli_ConsolidatedJointVenturesRealEstateAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ConsolidatedJointVenturesRealEstateAssets" xlink:to="cli_ConsolidatedJointVenturesRealEstateAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ConsolidatedJointVenturesRealEstateAssets_lbl" xml:lang="en-US">Consolidated Joint Ventures Real Estate Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ConsolidatedJointVenturesRealEstateAssets_lbl" xml:lang="en-US">Consolidated Joint Ventures Real Estate Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ConsolidatedJointVenturesRealEstateAssets_lbl" xml:lang="en-US">Consolidated joint ventures, total real estate assets</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ConsolidatedJointVenturesMortgages" xlink:label="cli_ConsolidatedJointVenturesMortgages" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ConsolidatedJointVenturesMortgages" xlink:to="cli_ConsolidatedJointVenturesMortgages_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ConsolidatedJointVenturesMortgages_lbl" xml:lang="en-US">Consolidated Joint Ventures Mortgages</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ConsolidatedJointVenturesMortgages_lbl" xml:lang="en-US">Consolidated Joint Ventures Mortgages</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ConsolidatedJointVenturesMortgages_lbl" xml:lang="en-US">Consolidated joint ventures, mortgages</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ConsolidatedJointVenturesOtherLiabilities" xlink:label="cli_ConsolidatedJointVenturesOtherLiabilities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ConsolidatedJointVenturesOtherLiabilities" xlink:to="cli_ConsolidatedJointVenturesOtherLiabilities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ConsolidatedJointVenturesOtherLiabilities_lbl" xml:lang="en-US">Consolidated Joint Ventures Other Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ConsolidatedJointVenturesOtherLiabilities_lbl" xml:lang="en-US">Consolidated Joint Ventures Other Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ConsolidatedJointVenturesOtherLiabilities_lbl" xml:lang="en-US">Consolidated joint ventures, other liabilities</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses" xlink:label="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses" xlink:to="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses_lbl" xml:lang="en-US">Capitalized Development, Construction Salaries And Other Related Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses_lbl" xml:lang="en-US">Capitalized Development, Construction Salaries And Other Related Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CapitalizedDevelopmentConstructionSalariesAndOtherRelatedExpenses_lbl" xml:lang="en-US">Capitalized development and construction salaries and other related costs</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete" xlink:label="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete" xlink:to="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete_lbl" xml:lang="en-US">Maximum Period After Cessation Of Major Construction Activity That Projects Are Considered Complete</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete_lbl" xml:lang="en-US">Maximum Period After Cessation Of Major Construction Activity That Projects Are Considered Complete</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MaximumPeriodAfterCessationOfMajorConstructionActivityThatProjectsAreConsideredComplete_lbl" xml:lang="en-US">Maximum period after cessation of major construction activity that projects are considered complete</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting" xlink:label="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting" xlink:to="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting_lbl" xml:lang="en-US">Threshold Of Investment Value For Discontinuation Of Equity Method Accounting</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting_lbl" xml:lang="en-US">Threshold Of Investment Value For Discontinuation Of Equity Method Accounting</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ThresholdOfInvestmentValueForDiscontinuationOfEquityMethodAccounting_lbl" xml:lang="en-US">Threshold of investment value for discontinuation of equity method accounting</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="us-gaap_AmortizationOfFinancingCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfFinancingCosts" xlink:to="us-gaap_AmortizationOfFinancingCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AmortizationOfFinancingCosts_lbl" xml:lang="en-US">Amortization of Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AmortizationOfFinancingCosts_lbl" xml:lang="en-US">Amortization of deferred financing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AmortizationOfDeferredLeasingFees" xlink:label="us-gaap_AmortizationOfDeferredLeasingFees" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfDeferredLeasingFees" xlink:to="us-gaap_AmortizationOfDeferredLeasingFees_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AmortizationOfDeferredLeasingFees_lbl" xml:lang="en-US">Amortization of Deferred Leasing Fees</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AmortizationOfDeferredLeasingFees_lbl" xml:lang="en-US">Deferred leasing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredTaxAssetsValuationAllowance" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsValuationAllowance" xlink:to="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xml:lang="en-US">Deferred tax asset</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DeferredTaxAssetsValuationAllowance_lbl" xml:lang="en-US">Valuation allowance</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MaterialAdjustmentAmount" xlink:label="cli_MaterialAdjustmentAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MaterialAdjustmentAmount" xlink:to="cli_MaterialAdjustmentAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MaterialAdjustmentAmount_lbl" xml:lang="en-US">Material Adjustment Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MaterialAdjustmentAmount_lbl" xml:lang="en-US">Material Adjustment Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MaterialAdjustmentAmount_lbl" xml:lang="en-US">Income taxes, material adjustment amount</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsOutstanding" xlink:label="cli_CommonUnitsOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsOutstanding" xlink:to="cli_CommonUnitsOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsOutstanding_lbl" xml:lang="en-US">The number of common units outstanding.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsOutstanding_lbl" xml:lang="en-US">Common Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="cli_CommonUnitsOutstanding_lbl" xml:lang="en-US">Balance, Ending, Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="cli_CommonUnitsOutstanding_lbl" xml:lang="en-US">Balance, Beginning, Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitsOutstanding_lbl" xml:lang="en-US">Common units outstanding</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermIncentivePlanUnitsOutstanding" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermIncentivePlanUnitsOutstanding" xlink:to="cli_LongTermIncentivePlanUnitsOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding_lbl" xml:lang="en-US">Long-Term Incentive Plan Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding_lbl" xml:lang="en-US">Long-Term Incentive Plan Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding_lbl" xml:lang="en-US">Balance, Ending, LTIP Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding_lbl" xml:lang="en-US">Balance, Beginning, LTIP Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LongTermIncentivePlanUnitsOutstanding_lbl" xml:lang="en-US">LTIP units outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear" xlink:to="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" xml:lang="en-US">Dividends Payable, Date of Record</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DividendsPayableDateOfRecordDayMonthAndYear_lbl" xml:lang="en-US">Distributions payable, record date</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear" xlink:to="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_lbl" xml:lang="en-US">Dividends Payable, Date Declared</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DividendsPayableDateDeclaredDayMonthAndYear_lbl" xml:lang="en-US">Distributions payable, approved date</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonStockDividendsAndCommonUnitDistributionsPerShare" xlink:label="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare" xlink:to="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare_lbl" xml:lang="en-US">Common Stock Dividends And Common Unit Distributions Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare_lbl" xml:lang="en-US">Common Stock Dividends And Common Unit Distributions Per Share</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonStockDividendsAndCommonUnitDistributionsPerShare_lbl" xml:lang="en-US">Common stock dividends and common unit distributions per share</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockExpense" xlink:label="us-gaap_RestrictedStockExpense" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedStockExpense" xlink:to="us-gaap_RestrictedStockExpense_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RestrictedStockExpense_lbl" xml:lang="en-US">Restricted Stock Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RestrictedStockExpense_lbl" xml:lang="en-US">Restricted stock expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DividendPayableDateToBePaidDayMonthAndYear" xlink:label="us-gaap_DividendPayableDateToBePaidDayMonthAndYear" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendPayableDateToBePaidDayMonthAndYear" xlink:to="us-gaap_DividendPayableDateToBePaidDayMonthAndYear_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendPayableDateToBePaidDayMonthAndYear_lbl" xml:lang="en-US">Dividends Payable, Date to be Paid, Day, Month and Year</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DividendPayableDateToBePaidDayMonthAndYear_lbl" xml:lang="en-US">Distributions payable, pay date</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:to="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_lbl" xml:lang="en-US">Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xml:lang="en-US">Federal income tax rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnNetIncome" xlink:label="us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnNetIncome" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfChangeOnNetIncome_lbl" xml:lang="en-US">Adjustment to retained earnings</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xml:lang="en-US">Property, Plant and Equipment [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandAndLandImprovements" xlink:label="us-gaap_LandAndLandImprovements" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandAndLandImprovements" xlink:to="us-gaap_LandAndLandImprovements_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LandAndLandImprovements_lbl" xml:lang="en-US">Land and Land Improvements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LandAndLandImprovements_lbl" xml:lang="en-US">Land held for development (including pre-development costs, if any)</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DevelopmentAndConstructionInProgressIncludingLand" xlink:label="cli_DevelopmentAndConstructionInProgressIncludingLand" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DevelopmentAndConstructionInProgressIncludingLand" xlink:to="cli_DevelopmentAndConstructionInProgressIncludingLand_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DevelopmentAndConstructionInProgressIncludingLand_lbl" xml:lang="en-US">Development And Construction In Progress, Including Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DevelopmentAndConstructionInProgressIncludingLand_lbl" xml:lang="en-US">Development And Construction In Progress, Including Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DevelopmentAndConstructionInProgressIncludingLand_lbl" xml:lang="en-US">Development and construction in progress, including land</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US">Property, Plant and Equipment, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US">Total</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation" xlink:label="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation" xlink:to="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation_lbl" xml:lang="en-US">Buildings And Improvements, Net Of Accumulated Depreciation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation_lbl" xml:lang="en-US">Buildings And Improvements, Net Of Accumulated Depreciation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_BuildingsAndImprovementsNetOfAccumulatedDepreciation_lbl" xml:lang="en-US">Buildings and improvement</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Land" xlink:label="us-gaap_Land" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Land" xlink:to="us-gaap_Land_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Land_lbl" xml:lang="en-US">Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_Land_lbl" xml:lang="en-US">Land</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:to="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_lbl" xml:lang="en-US">Schedule of Property, Plant and Equipment [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RangeAxis_lbl" xml:lang="en-US">Statistical Measurement [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RangeMember_lbl" xml:lang="en-US">Range [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_RangeMember_lbl" xml:lang="en-US">Range [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MinimumMember_lbl" xml:lang="en-US">Minimum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MinimumMember_lbl" xml:lang="en-US">Minimum [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MaximumMember_lbl" xml:lang="en-US">Maximum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MaximumMember_lbl" xml:lang="en-US">Maximum [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xml:lang="en-US">Property, Plant and Equipment by Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US">Property Plant And Equipment Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BuildingAndBuildingImprovementsMember" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingAndBuildingImprovementsMember" xlink:to="us-gaap_BuildingAndBuildingImprovementsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xml:lang="en-US">Building And Building Improvements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BuildingAndBuildingImprovementsMember_lbl" xml:lang="en-US">Buildings And Improvements [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="us-gaap_FurnitureAndFixturesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xml:lang="en-US">Furniture And Fixtures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xml:lang="en-US">Furniture, Fixtures And Equipment [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US">Property, Plant and Equipment, Useful Life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US">Estimated useful lives of assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfRealEstateProperties" xlink:label="us-gaap_NumberOfRealEstateProperties" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfRealEstateProperties" xlink:to="us-gaap_NumberOfRealEstateProperties_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NumberOfRealEstateProperties_lbl" xml:lang="en-US">Number of real estate properties</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NumberOfRealEstateProperties_lbl" xml:lang="en-US">Number of properties</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AreaOfRealEstateProperty" xlink:label="us-gaap_AreaOfRealEstateProperty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AreaOfRealEstateProperty" xlink:to="us-gaap_AreaOfRealEstateProperty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AreaOfRealEstateProperty_lbl" xml:lang="en-US">Area Of Real Estate Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:label="us-gaap_AreaOfRealEstateProperty_lbl" xml:lang="en-US">Area of property (in square feet)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AreaOfRealEstateProperty_lbl" xml:lang="en-US">Rentable Square Feet (sf)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AreaOfRealEstateProperty_lbl" xml:lang="en-US">Area of property (in square feet)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredUnitsIssued" xlink:label="us-gaap_PreferredUnitsIssued" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredUnitsIssued" xlink:to="us-gaap_PreferredUnitsIssued_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredUnitsIssued_lbl" xml:lang="en-US">Preferred Units, Issued</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredUnitsIssued_lbl" xml:lang="en-US">Preferred units shares issued</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:to="us-gaap_EquityMethodInvestmentOwnershipPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage_lbl" xml:lang="en-US">Equity Method Investment, Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage_lbl" xml:lang="en-US">Percentage of interest in venture</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_EquityMethodInvestmentOwnershipPercentage_lbl" xml:lang="en-US">Company's Effective Ownership %</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PreferredUnitDividendRatePercentage" xlink:label="cli_PreferredUnitDividendRatePercentage" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PreferredUnitDividendRatePercentage_lbl" xml:lang="en-US">Preferred Unit, Dividend Rate, Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PreferredUnitDividendRatePercentage_lbl" xml:lang="en-US">Preferred Unit, Dividend Rate, Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PreferredUnitDividendRatePercentage_lbl" xml:lang="en-US">Preferred unit annual rate</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentageOfAdditionalInterestAcquired" xlink:label="cli_PercentageOfAdditionalInterestAcquired" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentageOfAdditionalInterestAcquired" xlink:to="cli_PercentageOfAdditionalInterestAcquired_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentageOfAdditionalInterestAcquired_lbl" xml:lang="en-US">Percentage Of Additional Interest Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentageOfAdditionalInterestAcquired_lbl" xml:lang="en-US">Percentage Of Additional Interest Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentageOfAdditionalInterestAcquired_lbl" xml:lang="en-US">Percentage of additional interest acquired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xml:lang="en-US">Net assets acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xml:lang="en-US">Net assets</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfStoriesInRealEstateProperty" xlink:label="cli_NumberOfStoriesInRealEstateProperty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfStoriesInRealEstateProperty" xlink:to="cli_NumberOfStoriesInRealEstateProperty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfStoriesInRealEstateProperty_lbl" xml:lang="en-US">Number Of Stories In Real Estate Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfStoriesInRealEstateProperty_lbl" xml:lang="en-US">Number Of Stories In Real Estate Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfStoriesInRealEstateProperty_lbl" xml:lang="en-US">Number of stories</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MortgageLoanMaturityDate" xlink:label="cli_MortgageLoanMaturityDate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MortgageLoanMaturityDate" xlink:to="cli_MortgageLoanMaturityDate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MortgageLoanMaturityDate_lbl" xml:lang="en-US">Mortgage Loan Maturity Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MortgageLoanMaturityDate_lbl" xml:lang="en-US">Mortgage Loan Maturity Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MortgageLoanMaturityDate_lbl" xml:lang="en-US">Mortgage loan, maturity date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_MortgageLoanMaturityDate_lbl" xml:lang="en-US">Property Debt, Maturity Date</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xml:lang="en-US">Property Debt, Interest Rate, Spread Over LIBOR</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xml:lang="en-US">Spread over LIBOR</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xml:lang="en-US">Interest Rate - Applicable Basis Points Above LIBOR</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MortgageLoansOnRealEstate" xlink:label="us-gaap_MortgageLoansOnRealEstate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageLoansOnRealEstate" xlink:to="us-gaap_MortgageLoansOnRealEstate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageLoansOnRealEstate_lbl" xml:lang="en-US">Mortgage Loans on Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:label="us-gaap_MortgageLoansOnRealEstate_lbl" xml:lang="en-US">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageLoansOnRealEstate_lbl" xml:lang="en-US">Mortgage loan</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_MortgageLoansOnRealEstate_lbl" xml:lang="en-US">Carrying Amount of Mortgages</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RepaymentOfMortgageLoansOnRealEstate" xlink:label="cli_RepaymentOfMortgageLoansOnRealEstate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RepaymentOfMortgageLoansOnRealEstate" xlink:to="cli_RepaymentOfMortgageLoansOnRealEstate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RepaymentOfMortgageLoansOnRealEstate_lbl" xml:lang="en-US">Repayment Of Mortgage Loans On Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RepaymentOfMortgageLoansOnRealEstate_lbl" xml:lang="en-US">Repayment Of Mortgage Loans On Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RepaymentOfMortgageLoansOnRealEstate_lbl" xml:lang="en-US">Repayment of mortgage loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfDebt" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfDebt" xlink:to="us-gaap_ProceedsFromIssuanceOfDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt_lbl" xml:lang="en-US">Proceeds from Issuance of Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfDebt_lbl" xml:lang="en-US">Issuance of loan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="us-gaap_DebtInstrumentCarryingAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentCarryingAmount" xlink:to="us-gaap_DebtInstrumentCarryingAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xml:lang="en-US">Long-term Debt, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xml:lang="en-US">Loan balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentCarryingAmount_lbl" xml:lang="en-US">Principal balance outstanding</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfRealEstatePropertiesHeldForSale" xlink:label="cli_NumberOfRealEstatePropertiesHeldForSale" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfRealEstatePropertiesHeldForSale" xlink:to="cli_NumberOfRealEstatePropertiesHeldForSale_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfRealEstatePropertiesHeldForSale_lbl" xml:lang="en-US">Number Of Real Estate Properties Held For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfRealEstatePropertiesHeldForSale_lbl" xml:lang="en-US">Number Of Real Estate Properties Held For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfRealEstatePropertiesHeldForSale_lbl" xml:lang="en-US">Number of properties held for sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnrealizedGainLossOnInvestments" xlink:label="us-gaap_UnrealizedGainLossOnInvestments" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnrealizedGainLossOnInvestments" xlink:to="us-gaap_UnrealizedGainLossOnInvestments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UnrealizedGainLossOnInvestments_lbl" xml:lang="en-US">Unrealized Gain (Loss) on Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_UnrealizedGainLossOnInvestments_lbl" xml:lang="en-US">Unrealized losses on rental properties held for sale</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment" xlink:label="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment" xlink:to="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment_lbl" xml:lang="en-US">Estimated Proceeds From Sale Of Real Estate Held For Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment_lbl" xml:lang="en-US">Estimated Proceeds From Sale Of Real Estate Held For Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_EstimatedProceedsFromSaleOfRealEstateHeldForInvestment_lbl" xml:lang="en-US">Estimated expected sales proceeds</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets" xlink:to="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges And Other Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges And Other Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredChargesAndOtherAssets_lbl" xml:lang="en-US">Assets held for sale, Deferred charges and other assets</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet" xlink:to="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Deferred Rent Receivables, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Deferred Rent Receivables, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupDeferredRentReceivablesNet_lbl" xml:lang="en-US">Assets held for sale, Unbilled rents receivable, net</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities" xlink:to="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Accrued Expenses And Other Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Accrued Expenses And Other Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupAccountsPayableAccruedExpensesAndOtherLiabilities_lbl" xml:lang="en-US">Assets held for sale, Accounts payable, accrued expenses and other liabilities</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff" xlink:to="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Expected Asset To Be Written Off</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Assets Held-for-sale, Not Part of Disposal Group, Expected Asset To Be Written Off</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsHeldForSaleNotPartOfDisposalGroupExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Expected assets to be written off</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff" xlink:to="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Liabilities, Expected Asset To Be Written Off</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Liabilities, Expected Asset To Be Written Off</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationLiabilitiesExpectedAssetToBeWrittenOff_lbl" xml:lang="en-US">Expected liabilities to be written off</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfBuildingsOnPropertiesSold" xlink:label="cli_NumberOfBuildingsOnPropertiesSold" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfBuildingsOnPropertiesSold" xlink:to="cli_NumberOfBuildingsOnPropertiesSold_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfBuildingsOnPropertiesSold_lbl" xml:lang="en-US">Number Of Buildings On Properties Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfBuildingsOnPropertiesSold_lbl" xml:lang="en-US">Number of buildings on properties sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfBuildingsOnPropertiesSold_lbl" xml:lang="en-US">Number of Buildings, Disposed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_NumberOfBuildingsOnPropertiesSold_lbl" xml:lang="en-US">Number of properties sold</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainOnSaleOfInvestments" xlink:label="us-gaap_GainOnSaleOfInvestments" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainOnSaleOfInvestments" xlink:to="us-gaap_GainOnSaleOfInvestments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainOnSaleOfInvestments_lbl" xml:lang="en-US">Gain on Sale of Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GainOnSaleOfInvestments_lbl" xml:lang="en-US">Gain on sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:to="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_lbl" xml:lang="en-US">Schedule of Business Acquisitions, by Acquisition [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="us-gaap_BusinessAcquisitionLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionLineItems" xlink:to="us-gaap_BusinessAcquisitionLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionLineItems_lbl" xml:lang="en-US">Business Acquisition [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfPropertiesAcquired" xlink:label="cli_NumberOfPropertiesAcquired" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfPropertiesAcquired" xlink:to="cli_NumberOfPropertiesAcquired_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfPropertiesAcquired_lbl" xml:lang="en-US">Number Of Properties Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfPropertiesAcquired_lbl" xml:lang="en-US">Number Of Properties Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfPropertiesAcquired_lbl" xml:lang="en-US">Number of Buildings, Acquired</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AreaOfRealEstatePropertyAcquired" xlink:label="cli_AreaOfRealEstatePropertyAcquired" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AreaOfRealEstatePropertyAcquired" xlink:to="cli_AreaOfRealEstatePropertyAcquired_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AreaOfRealEstatePropertyAcquired_lbl" xml:lang="en-US">Area Of Real Estate Property Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AreaOfRealEstatePropertyAcquired_lbl" xml:lang="en-US">Area Of Real Estate Property Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AreaOfRealEstatePropertyAcquired_lbl" xml:lang="en-US">Rentable Square Feet, Acquired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationConsiderationTransferred1_lbl" xml:lang="en-US">Acquisition cost</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLand_lbl" xml:lang="en-US">Land and leasehold interest</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Buildings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings_lbl" xml:lang="en-US">Buildings and improvements and other assets, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBuildings_lbl" xml:lang="en-US">Buildings and improvements and other assets</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases" xlink:to="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Above Market Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Above Market Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAboveMarketLeases_lbl" xml:lang="en-US">Above market lease values</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases" xlink:to="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, In Place Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, In Place Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInPlaceLeases_lbl" xml:lang="en-US">In-place lease values</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Assets Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets_lbl" xml:lang="en-US">Sub Total</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases" xlink:to="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Below Market Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases_lbl" xml:lang="en-US">Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed, Below Market Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedBelowMarketLeases_lbl" xml:lang="en-US">Less: Below market lease values</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:label="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue" xlink:to="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_lbl" xml:lang="en-US">Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_lbl" xml:lang="en-US">Less: Noncontrolling interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue_lbl" xml:lang="en-US">Non-controlling interest</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife" xlink:to="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" xml:lang="en-US">Finite-Lived Intangible Asset, Useful Life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_lbl" xml:lang="en-US">Amortization period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Liabilities Assumed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedLiabilities_lbl" xml:lang="en-US">Less: Debt assumed at fair value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest_lbl" xml:lang="en-US">Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedLessNoncontrollingInterest_lbl" xml:lang="en-US">Net assets recorded upon consolidation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_lbl" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems" xlink:to="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_lbl" xml:lang="en-US">Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfPropertiesDisposed" xlink:label="cli_NumberOfPropertiesDisposed" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfPropertiesDisposed" xlink:to="cli_NumberOfPropertiesDisposed_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfPropertiesDisposed_lbl" xml:lang="en-US">Number Of Properties Disposed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfPropertiesDisposed_lbl" xml:lang="en-US">Number Of Properties Disposed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfPropertiesDisposed_lbl" xml:lang="en-US">Number of properties disposed</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AreaOfRealEstatePropertySold" xlink:label="cli_AreaOfRealEstatePropertySold" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AreaOfRealEstatePropertySold" xlink:to="cli_AreaOfRealEstatePropertySold_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AreaOfRealEstatePropertySold_lbl" xml:lang="en-US">Area Of Real Estate Property Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AreaOfRealEstatePropertySold_lbl" xml:lang="en-US">Area Of Real Estate Property Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AreaOfRealEstatePropertySold_lbl" xml:lang="en-US">Rentable Square Feet, Disposed</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:label="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:to="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_lbl" xml:lang="en-US">Proceeds from Sale of Real Estate Held-for-investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_lbl" xml:lang="en-US">Net Sales Proceeds</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_lbl" xml:lang="en-US">Sales proceeds</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue" xlink:to="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue_lbl" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Net Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue_lbl" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Net Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="cli_DisposalGroupIncludingDiscontinuedOperationPropertyPlantAndEquipmentNetValue_lbl" xml:lang="en-US">Net Carrying Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations" xlink:label="us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations" xlink:to="us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations_lbl" xml:lang="en-US">Gain (Loss) on Disposition of Real Estate, Discontinued Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_GainLossOnDispositionOfRealEstateDiscontinuedOperations_lbl" xml:lang="en-US">Realized Gains (losses)/Unrealized Losses, net</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InternalRateOfReturn" xlink:label="cli_InternalRateOfReturn" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InternalRateOfReturn" xlink:to="cli_InternalRateOfReturn_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InternalRateOfReturn_lbl" xml:lang="en-US">Internal Rate of Return</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InternalRateOfReturn_lbl" xml:lang="en-US">Internal rate of return</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InternalRateOfReturn_lbl" xml:lang="en-US">Internal rate of return</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses" xlink:label="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses" xlink:to="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses_lbl" xml:lang="en-US">Gain (Loss) On Disposition Of Real Estate Discontinued Operations, Net Of Unrealized Gain (Losses)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses_lbl" xml:lang="en-US">Gain (Loss) On Disposition Of Real Estate Discontinued Operations, Net Of Unrealized Gain (Losses)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="cli_GainLossOnDispositionOfRealEstateDiscontinuedOperationsNetOfUnrealizedGainLosses_lbl" xml:lang="en-US">Totals</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" xlink:label="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" xlink:to="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Proceeds From Sale Of Real Estate Held For Investment, Held By A Qualified Intermediary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Proceeds From Sale Of Real Estate Held For Investment, Held By A Qualified Intermediary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Net sales proceeds held by qualified intermediary</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentNumberOfExtensionOptions" xlink:label="cli_DebtInstrumentNumberOfExtensionOptions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentNumberOfExtensionOptions" xlink:to="cli_DebtInstrumentNumberOfExtensionOptions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentNumberOfExtensionOptions_lbl" xml:lang="en-US">Debt Instrument, Number Of Extension Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentNumberOfExtensionOptions_lbl" xml:lang="en-US">Debt Instrument, Number Of Extension Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentNumberOfExtensionOptions_lbl" xml:lang="en-US">Number of extension options</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentExtensionPeriod" xlink:label="cli_DebtInstrumentExtensionPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentExtensionPeriod" xlink:to="cli_DebtInstrumentExtensionPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentExtensionPeriod_lbl" xml:lang="en-US">Debt Instrument Extension Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentExtensionPeriod_lbl" xml:lang="en-US">Debt Instrument Extension Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentExtensionPeriod_lbl" xml:lang="en-US">Loan extension period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NotesReceivableGross" xlink:label="us-gaap_NotesReceivableGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NotesReceivableGross" xlink:to="us-gaap_NotesReceivableGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NotesReceivableGross_lbl" xml:lang="en-US">Financing Receivable, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NotesReceivableGross_lbl" xml:lang="en-US">Mortgage receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromSaleOfRealEstate" xlink:label="us-gaap_ProceedsFromSaleOfRealEstate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfRealEstate" xlink:to="us-gaap_ProceedsFromSaleOfRealEstate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfRealEstate_lbl" xml:lang="en-US">Proceeds from Sale of Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromSaleOfRealEstate_lbl" xml:lang="en-US">Proceeds from sale of properties</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" xlink:label="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary" xlink:to="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Payments To Acquire And Develop Real Estate, Funds From Proceeds From Sale Of Real Estate Held For Investment, Held By A Qualified Intermediary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Payments To Acquire And Develop Real Estate, Funds From Proceeds From Sale Of Real Estate Held For Investment, Held By A Qualified Intermediary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsToAcquireAndDevelopRealEstateFundsFromProceedsFromSaleOfRealEstateHeldForInvestmentHeldByQualifiedIntermediary_lbl" xml:lang="en-US">Funds from qualified intermediary</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LandAvailableForSale" xlink:label="us-gaap_LandAvailableForSale" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandAvailableForSale" xlink:to="us-gaap_LandAvailableForSale_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LandAvailableForSale_lbl" xml:lang="en-US">Land Available-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LandAvailableForSale_lbl" xml:lang="en-US">Land</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_BuildingsAndImprovementsAvailableForSale" xlink:label="cli_BuildingsAndImprovementsAvailableForSale" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_BuildingsAndImprovementsAvailableForSale" xlink:to="cli_BuildingsAndImprovementsAvailableForSale_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_BuildingsAndImprovementsAvailableForSale_lbl" xml:lang="en-US">Buildings And Improvements Available For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_BuildingsAndImprovementsAvailableForSale_lbl" xml:lang="en-US">Buildings And Improvements Available For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_BuildingsAndImprovementsAvailableForSale_lbl" xml:lang="en-US">Buildings and improvements</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnrealizedGainLossOnInvestmentsHeldForSale" xlink:label="cli_UnrealizedGainLossOnInvestmentsHeldForSale" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnrealizedGainLossOnInvestmentsHeldForSale" xlink:to="cli_UnrealizedGainLossOnInvestmentsHeldForSale_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnrealizedGainLossOnInvestmentsHeldForSale_lbl" xml:lang="en-US">Unrealized Gain Loss On Investments Held For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnrealizedGainLossOnInvestmentsHeldForSale_lbl" xml:lang="en-US">Unrealized Gain Loss On Investments Held For Sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_UnrealizedGainLossOnInvestmentsHeldForSale_lbl" xml:lang="en-US">Less: Cumulative unrealized losses on property held for sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsTable" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsTable_lbl" xml:lang="en-US">Schedule of Equity Method Investments [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:label="us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis" xlink:to="us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis_lbl" xml:lang="en-US">Variable Interest Entities [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:label="us-gaap_ClassificationOfVariableInterestEntityDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ClassificationOfVariableInterestEntityDomain" xlink:to="us-gaap_ClassificationOfVariableInterestEntityDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ClassificationOfVariableInterestEntityDomain_lbl" xml:lang="en-US">Classification Of Variable Interest Entity [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ClassificationOfVariableInterestEntityDomain_lbl" xml:lang="en-US">Variable Interest Entity, Classification [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember" xlink:label="us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember" xlink:to="us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_lbl" xml:lang="en-US">Variable Interest Entity Not Primary Beneficiary [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_VariableInterestEntityNotPrimaryBeneficiaryMember_lbl" xml:lang="en-US">Variable Interest Entity [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureRetailBuildingsMember" xlink:label="cli_UnconsolidatedJointVentureRetailBuildingsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureRetailBuildingsMember" xlink:to="cli_UnconsolidatedJointVentureRetailBuildingsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Retail Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Retail Buildings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureRetailBuildingsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Retail Buildings [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureHotelMember" xlink:label="cli_UnconsolidatedJointVentureHotelMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureHotelMember" xlink:to="cli_UnconsolidatedJointVentureHotelMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureHotelMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Hotel [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureDevelopmentProjectsMember" xlink:label="cli_UnconsolidatedJointVentureDevelopmentProjectsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureDevelopmentProjectsMember" xlink:to="cli_UnconsolidatedJointVentureDevelopmentProjectsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureDevelopmentProjectsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Development Projects [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureDevelopmentProjectsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Development Projects [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureDevelopmentProjectsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Development Projects [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVentureLandParcelsMember" xlink:label="cli_UnconsolidatedJointVentureLandParcelsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVentureLandParcelsMember" xlink:to="cli_UnconsolidatedJointVentureLandParcelsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVentureLandParcelsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Land Parcels [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVentureLandParcelsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Land Parcels [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVentureLandParcelsMember_lbl" xml:lang="en-US">Unconsolidated Joint Venture Land Parcels [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnconsolidatedJointVenturesMember" xlink:label="cli_UnconsolidatedJointVenturesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnconsolidatedJointVenturesMember" xlink:to="cli_UnconsolidatedJointVenturesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnconsolidatedJointVenturesMember_lbl" xml:lang="en-US">Unconsolidated Joint Ventures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnconsolidatedJointVenturesMember_lbl" xml:lang="en-US">Unconsolidated Joint Ventures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnconsolidatedJointVenturesMember_lbl" xml:lang="en-US">Unconsolidated Joint Ventures [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems" xlink:to="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_lbl" xml:lang="en-US">Schedule of Equity Method Investments [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AreaOfMixedUseProperty" xlink:label="cli_AreaOfMixedUseProperty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AreaOfMixedUseProperty" xlink:to="cli_AreaOfMixedUseProperty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AreaOfMixedUseProperty_lbl" xml:lang="en-US">Area Of Mixed Use Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AreaOfMixedUseProperty_lbl" xml:lang="en-US">Area Of Mixed Use Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AreaOfMixedUseProperty_lbl" xml:lang="en-US">Area of mixed use project (in square feet)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US">Maximum borrowing capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US">Borrowing capacity under the credit facility</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ManagementLeasingDevelopmentAndOtherServicesFees" xlink:label="cli_ManagementLeasingDevelopmentAndOtherServicesFees" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ManagementLeasingDevelopmentAndOtherServicesFees" xlink:to="cli_ManagementLeasingDevelopmentAndOtherServicesFees_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ManagementLeasingDevelopmentAndOtherServicesFees_lbl" xml:lang="en-US">Management, Leasing, Development And Other Services Fees</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ManagementLeasingDevelopmentAndOtherServicesFees_lbl" xml:lang="en-US">Management, Leasing, Development And Other Services Fees</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ManagementLeasingDevelopmentAndOtherServicesFees_lbl" xml:lang="en-US">Management, leasing, development and other services fees</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DueFromJointVentures" xlink:label="us-gaap_DueFromJointVentures" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DueFromJointVentures" xlink:to="us-gaap_DueFromJointVentures_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DueFromJointVentures_lbl" xml:lang="en-US">Due from Joint Ventures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DueFromJointVentures_lbl" xml:lang="en-US">Accounts receivable due from unconsolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfVariableInterestEntities" xlink:label="cli_NumberOfVariableInterestEntities" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfVariableInterestEntities" xlink:to="cli_NumberOfVariableInterestEntities_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfVariableInterestEntities_lbl" xml:lang="en-US">Number Of Variable Interest Entities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfVariableInterestEntities_lbl" xml:lang="en-US">Number Of Variable Interest Entities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfVariableInterestEntities_lbl" xml:lang="en-US">Number of VIEs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" xlink:label="us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" xlink:to="us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_lbl" xml:lang="en-US">Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_lbl" xml:lang="en-US">Maximum exposure to loss</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments" xlink:label="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments" xlink:to="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments_lbl" xml:lang="en-US">Variable Interest Entity, Entity Estimated Future Funding Commitments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments_lbl" xml:lang="en-US">Variable Interest Entity, Entity Estimated Future Funding Commitments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_VariableInterestEntityEntityEstimatedFutureFundingCommitments_lbl" xml:lang="en-US">Estimated future funding commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xml:lang="en-US">Property Debt, Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xml:lang="en-US">Interest rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xml:lang="en-US">Interest rate of senior unsecured notes</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermLineOfCreditMaximumGuaranteedAmount" xlink:label="cli_LongTermLineOfCreditMaximumGuaranteedAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermLineOfCreditMaximumGuaranteedAmount" xlink:to="cli_LongTermLineOfCreditMaximumGuaranteedAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermLineOfCreditMaximumGuaranteedAmount_lbl" xml:lang="en-US">Long-term Line of Credit, Maximum Guaranteed Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermLineOfCreditMaximumGuaranteedAmount_lbl" xml:lang="en-US">Long-term Line of Credit, Maximum Guaranteed Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LongTermLineOfCreditMaximumGuaranteedAmount_lbl" xml:lang="en-US">Maximum guaranteed amount</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermLineOfCreditGuaranteedAmount" xlink:label="cli_LongTermLineOfCreditGuaranteedAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermLineOfCreditGuaranteedAmount" xlink:to="cli_LongTermLineOfCreditGuaranteedAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermLineOfCreditGuaranteedAmount_lbl" xml:lang="en-US">Long-term Line of Credit, Guaranteed Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermLineOfCreditGuaranteedAmount_lbl" xml:lang="en-US">Long-term Line of Credit, Guaranteed Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LongTermLineOfCreditGuaranteedAmount_lbl" xml:lang="en-US">Guaranteed amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:label="srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis" xlink:to="srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_lbl" xml:lang="en-US">Name of Property [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:label="srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain" xlink:to="srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_lbl" xml:lang="en-US">Real Estate And Accumulated Depreciation Name Of Property [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_lbl" xml:lang="en-US">Name of Property [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShopsAtFortyParkPropertyMember" xlink:label="cli_ShopsAtFortyParkPropertyMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShopsAtFortyParkPropertyMember" xlink:to="cli_ShopsAtFortyParkPropertyMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShopsAtFortyParkPropertyMember_lbl" xml:lang="en-US">The Shops At Forty Park Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShopsAtFortyParkPropertyMember_lbl" xml:lang="en-US">Shops At Forty Park Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShopsAtFortyParkPropertyMember_lbl" xml:lang="en-US">The Shops At 40 Park Property [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LoftsAtFortyParkPropertyMember" xlink:label="cli_LoftsAtFortyParkPropertyMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LoftsAtFortyParkPropertyMember" xlink:to="cli_LoftsAtFortyParkPropertyMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LoftsAtFortyParkPropertyMember_lbl" xml:lang="en-US">Lofts At 40 Park Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LoftsAtFortyParkPropertyMember_lbl" xml:lang="en-US">Lofts At Forty Park Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LoftsAtFortyParkPropertyMember_lbl" xml:lang="en-US">Lofts At 40 Park Property [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MetropolitanPropertyMember" xlink:label="cli_MetropolitanPropertyMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MetropolitanPropertyMember" xlink:to="cli_MetropolitanPropertyMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MetropolitanPropertyMember_lbl" xml:lang="en-US">Metropolitan Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MetropolitanPropertyMember_lbl" xml:lang="en-US">Metropolitan Property [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MetropolitanPropertyMember_lbl" xml:lang="en-US">Metropolitan Property [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_lbl" xml:lang="en-US">Investment, Name [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="srt_EquityMethodInvesteeNameDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_EquityMethodInvesteeNameDomain" xlink:to="srt_EquityMethodInvesteeNameDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_EquityMethodInvesteeNameDomain_lbl" xml:lang="en-US">Equity Method Investee Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_EquityMethodInvesteeNameDomain_lbl" xml:lang="en-US">Equity Method Investee, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedBankCorporatePlazaLLCMember" xlink:label="cli_RedBankCorporatePlazaLLCMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedBankCorporatePlazaLLCMember" xlink:to="cli_RedBankCorporatePlazaLLCMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedBankCorporatePlazaLLCMember_lbl" xml:lang="en-US">Red Bank Corporate Plaza, L.L.C. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedBankCorporatePlazaLLCMember_lbl" xml:lang="en-US">Red Bank Corporate Plaza L L C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RedBankCorporatePlazaLLCMember_lbl" xml:lang="en-US">Red Bank [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TwelveVreelandAssociatesLLCMember" xlink:label="cli_TwelveVreelandAssociatesLLCMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TwelveVreelandAssociatesLLCMember" xlink:to="cli_TwelveVreelandAssociatesLLCMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TwelveVreelandAssociatesLLCMember_lbl" xml:lang="en-US">12 Vreeland Associates, L.L.C. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwelveVreelandAssociatesLLCMember_lbl" xml:lang="en-US">Twelve Vreeland Associates L L C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwelveVreelandAssociatesLLCMember_lbl" xml:lang="en-US">12 Vreeland Road [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MetropolitanAt40ParkMember" xlink:label="cli_MetropolitanAt40ParkMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MetropolitanAt40ParkMember" xlink:to="cli_MetropolitanAt40ParkMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MetropolitanAt40ParkMember_lbl" xml:lang="en-US">Metropolitan At 40 Park [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MetropolitanAt40ParkMember_lbl" xml:lang="en-US">Metropolitan At40 Park [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MetropolitanAt40ParkMember_lbl" xml:lang="en-US">Metropolitan At 40 Park [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RivertraceAtPortImperialMember" xlink:label="cli_RivertraceAtPortImperialMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RivertraceAtPortImperialMember" xlink:to="cli_RivertraceAtPortImperialMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RivertraceAtPortImperialMember_lbl" xml:lang="en-US">RiverTrace At Port Imperial [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RivertraceAtPortImperialMember_lbl" xml:lang="en-US">Rivertrace At Port Imperial [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RivertraceAtPortImperialMember_lbl" xml:lang="en-US">RiverTrace At Port Imperial [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OfficesAtCrystalLakeMember" xlink:label="cli_OfficesAtCrystalLakeMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OfficesAtCrystalLakeMember" xlink:to="cli_OfficesAtCrystalLakeMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OfficesAtCrystalLakeMember_lbl" xml:lang="en-US">Offices At Crystal Lake [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OfficesAtCrystalLakeMember_lbl" xml:lang="en-US">Offices At Crystal Lake [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_OfficesAtCrystalLakeMember_lbl" xml:lang="en-US">Offices At Crystal Lake [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RiverwalkRetailMember" xlink:label="cli_RiverwalkRetailMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RiverwalkRetailMember" xlink:to="cli_RiverwalkRetailMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RiverwalkRetailMember_lbl" xml:lang="en-US">Riverwalk Retail [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RiverwalkRetailMember_lbl" xml:lang="en-US">Riverwalk Retail [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RiverwalkRetailMember_lbl" xml:lang="en-US">Riverwalk Retail [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_HyattRegencyJerseyCityMember" xlink:label="cli_HyattRegencyJerseyCityMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_HyattRegencyJerseyCityMember" xlink:to="cli_HyattRegencyJerseyCityMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_HyattRegencyJerseyCityMember_lbl" xml:lang="en-US">Hyatt Regency Jersey City [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_HyattRegencyJerseyCityMember_lbl" xml:lang="en-US">Hyatt Regency Jersey City [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_HyattRegencyJerseyCityMember_lbl" xml:lang="en-US">Hyatt Regency Jersey City [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RiverparkAtHarrisonMember" xlink:label="cli_RiverparkAtHarrisonMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RiverparkAtHarrisonMember" xlink:to="cli_RiverparkAtHarrisonMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RiverparkAtHarrisonMember_lbl" xml:lang="en-US">Riverpark At Harrison [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RiverparkAtHarrisonMember_lbl" xml:lang="en-US">Riverpark At Harrison [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RiverparkAtHarrisonMember_lbl" xml:lang="en-US">Riverpark At Harrison [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StationHouseMember" xlink:label="cli_StationHouseMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_StationHouseMember" xlink:to="cli_StationHouseMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StationHouseMember_lbl" xml:lang="en-US">Station House [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StationHouseMember_lbl" xml:lang="en-US">Station House [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_StationHouseMember_lbl" xml:lang="en-US">Station House [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UrbyAtHarborsideMember" xlink:label="cli_UrbyAtHarborsideMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UrbyAtHarborsideMember" xlink:to="cli_UrbyAtHarborsideMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UrbyAtHarborsideMember_lbl" xml:lang="en-US">Urby At Harborside [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UrbyAtHarborsideMember_lbl" xml:lang="en-US">Urby At Harborside [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UrbyAtHarborsideMember_lbl" xml:lang="en-US">Urby At Harborside [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PiNorthLandMember" xlink:label="cli_PiNorthLandMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PiNorthLandMember" xlink:to="cli_PiNorthLandMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PiNorthLandMember_lbl" xml:lang="en-US">PI North - Land [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PiNorthLandMember_lbl" xml:lang="en-US">Pi North Land [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PiNorthLandMember_lbl" xml:lang="en-US">PI North - Land [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LibertyLandingMember" xlink:label="cli_LibertyLandingMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LibertyLandingMember" xlink:to="cli_LibertyLandingMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LibertyLandingMember_lbl" xml:lang="en-US">Liberty Landing [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LibertyLandingMember_lbl" xml:lang="en-US">Liberty Landing [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LibertyLandingMember_lbl" xml:lang="en-US">Liberty Landing [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_HillsboroughTwoHundredSixHoldingsLLCMember" xlink:label="cli_HillsboroughTwoHundredSixHoldingsLLCMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_HillsboroughTwoHundredSixHoldingsLLCMember" xlink:to="cli_HillsboroughTwoHundredSixHoldingsLLCMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_HillsboroughTwoHundredSixHoldingsLLCMember_lbl" xml:lang="en-US">Hillsborough 206 Holdings, L.L.C. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_HillsboroughTwoHundredSixHoldingsLLCMember_lbl" xml:lang="en-US">Hillsborough Two Hundred Six Holdings L L C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_HillsboroughTwoHundredSixHoldingsLLCMember_lbl" xml:lang="en-US">Hillsborough 206 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CrystalHouseApartmentsInvestorsLLCMember" xlink:label="cli_CrystalHouseApartmentsInvestorsLLCMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CrystalHouseApartmentsInvestorsLLCMember" xlink:to="cli_CrystalHouseApartmentsInvestorsLLCMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CrystalHouseApartmentsInvestorsLLCMember_lbl" xml:lang="en-US">Crystal House Apartments Investors LLC [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CrystalHouseApartmentsInvestorsLLCMember_lbl" xml:lang="en-US">Crystal House Apartments Investors L L C [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CrystalHouseApartmentsInvestorsLLCMember_lbl" xml:lang="en-US">Crystal House [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PiNorthRiverwalkMember" xlink:label="cli_PiNorthRiverwalkMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PiNorthRiverwalkMember" xlink:to="cli_PiNorthRiverwalkMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PiNorthRiverwalkMember_lbl" xml:lang="en-US">PI North - Riverwalk [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PiNorthRiverwalkMember_lbl" xml:lang="en-US">Pi North Riverwalk [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PiNorthRiverwalkMember_lbl" xml:lang="en-US">PI North - Riverwalk C [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MarbellaIiMember" xlink:label="cli_MarbellaIiMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MarbellaIiMember" xlink:to="cli_MarbellaIiMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MarbellaIiMember_lbl" xml:lang="en-US">Marbella II [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MarbellaIiMember_lbl" xml:lang="en-US">Marbella Ii [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MarbellaIiMember_lbl" xml:lang="en-US">Marbella II [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OtherJointVenturesMember" xlink:label="cli_OtherJointVenturesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OtherJointVenturesMember" xlink:to="cli_OtherJointVenturesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OtherJointVenturesMember_lbl" xml:lang="en-US">Other Joint Ventures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OtherJointVenturesMember_lbl" xml:lang="en-US">Other Joint Ventures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_OtherJointVenturesMember_lbl" xml:lang="en-US">Other [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LiborInterestRate" xlink:label="cli_LiborInterestRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LiborInterestRate" xlink:to="cli_LiborInterestRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LiborInterestRate_lbl" xml:lang="en-US">Libor Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LiborInterestRate_lbl" xml:lang="en-US">Libor Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LiborInterestRate_lbl" xml:lang="en-US">LIBOR</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_LiborInterestRate_lbl" xml:lang="en-US">Property Debt, Interest Rate, LIBOR</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ResidualOwnershipInterest" xlink:label="cli_ResidualOwnershipInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ResidualOwnershipInterest" xlink:to="cli_ResidualOwnershipInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ResidualOwnershipInterest_lbl" xml:lang="en-US">Residual Ownership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ResidualOwnershipInterest_lbl" xml:lang="en-US">Residual Ownership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ResidualOwnershipInterest_lbl" xml:lang="en-US">Residual ownership interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IndirectOwnershipPercentage" xlink:label="cli_IndirectOwnershipPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IndirectOwnershipPercentage" xlink:to="cli_IndirectOwnershipPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IndirectOwnershipPercentage_lbl" xml:lang="en-US">Indirect Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IndirectOwnershipPercentage_lbl" xml:lang="en-US">Indirect Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_IndirectOwnershipPercentage_lbl" xml:lang="en-US">Indirect ownership interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentExtensionFeePercentage" xlink:label="cli_DebtInstrumentExtensionFeePercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentExtensionFeePercentage" xlink:to="cli_DebtInstrumentExtensionFeePercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentExtensionFeePercentage_lbl" xml:lang="en-US">Debt Instrument Extension Fee Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentExtensionFeePercentage_lbl" xml:lang="en-US">Debt Instrument Extension Fee Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentExtensionFeePercentage_lbl" xml:lang="en-US">Extension fee</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentageOfInterestInDevelopableLand" xlink:label="cli_PercentageOfInterestInDevelopableLand" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentageOfInterestInDevelopableLand" xlink:to="cli_PercentageOfInterestInDevelopableLand_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentageOfInterestInDevelopableLand_lbl" xml:lang="en-US">Percentage Of Interest In Developable Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentageOfInterestInDevelopableLand_lbl" xml:lang="en-US">Percentage Of Interest In Developable Land</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentageOfInterestInDevelopableLand_lbl" xml:lang="en-US">Percentage of interest in developable land</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateEffectivePercentage" xlink:to="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xml:lang="en-US">Debt Instrument, Interest Rate, Effective Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentInterestRateEffectivePercentage_lbl" xml:lang="en-US">Effective rate</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfUnitsAvailableForDevelopment" xlink:label="cli_NumberOfUnitsAvailableForDevelopment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfUnitsAvailableForDevelopment" xlink:to="cli_NumberOfUnitsAvailableForDevelopment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number Of Units Available For Development</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number Of Units Available For Development</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number of units available for development</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfApprovedUnitsAvailableForDevelopment" xlink:label="cli_NumberOfApprovedUnitsAvailableForDevelopment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfApprovedUnitsAvailableForDevelopment" xlink:to="cli_NumberOfApprovedUnitsAvailableForDevelopment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfApprovedUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number Of Approved Units Available For Development</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfApprovedUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number Of Approved Units Available For Development</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfApprovedUnitsAvailableForDevelopment_lbl" xml:lang="en-US">Number of approved units available for development</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentMaturityDate" xlink:label="us-gaap_DebtInstrumentMaturityDate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentMaturityDate" xlink:to="us-gaap_DebtInstrumentMaturityDate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xml:lang="en-US">Mortgage loan, maturity date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xml:lang="en-US">Loan maturity date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentMaturityDate_lbl" xml:lang="en-US">Maturity date of the senior unsecured notes</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentageOfInterestSold" xlink:label="cli_PercentageOfInterestSold" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentageOfInterestSold" xlink:to="cli_PercentageOfInterestSold_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentageOfInterestSold_lbl" xml:lang="en-US">Percentage Of Interest Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentageOfInterestSold_lbl" xml:lang="en-US">Percentage Of Interest Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentageOfInterestSold_lbl" xml:lang="en-US">Percentage of interest sold</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_EquityMethodInvestmentAmortizationOfBasisDifference" xlink:label="cli_EquityMethodInvestmentAmortizationOfBasisDifference" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_EquityMethodInvestmentAmortizationOfBasisDifference" xlink:to="cli_EquityMethodInvestmentAmortizationOfBasisDifference_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_EquityMethodInvestmentAmortizationOfBasisDifference_lbl" xml:lang="en-US">Equity Method Investment, Amortization Of Basis Difference</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_EquityMethodInvestmentAmortizationOfBasisDifference_lbl" xml:lang="en-US">Equity Method Investment, Amortization Of Basis Difference</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_EquityMethodInvestmentAmortizationOfBasisDifference_lbl" xml:lang="en-US">Amortization of basis difference</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncomeFromSaleOfEconomicTaxCreditCertificate" xlink:label="cli_IncomeFromSaleOfEconomicTaxCreditCertificate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncomeFromSaleOfEconomicTaxCreditCertificate" xlink:to="cli_IncomeFromSaleOfEconomicTaxCreditCertificate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IncomeFromSaleOfEconomicTaxCreditCertificate_lbl" xml:lang="en-US">Income From Sale Of Economic Tax Credit Certificate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncomeFromSaleOfEconomicTaxCreditCertificate_lbl" xml:lang="en-US">Income From Sale Of Economic Tax Credit Certificate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_IncomeFromSaleOfEconomicTaxCreditCertificate_lbl" xml:lang="en-US">Economic tax credit certificate income</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PeriodOfVentureAgreementWithThirdParty" xlink:label="cli_PeriodOfVentureAgreementWithThirdParty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PeriodOfVentureAgreementWithThirdParty" xlink:to="cli_PeriodOfVentureAgreementWithThirdParty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PeriodOfVentureAgreementWithThirdParty_lbl" xml:lang="en-US">Period Of Venture Agreement With Third Party</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PeriodOfVentureAgreementWithThirdParty_lbl" xml:lang="en-US">Period Of Venture Agreement With Third Party</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PeriodOfVentureAgreementWithThirdParty_lbl" xml:lang="en-US">Period of venture agreement to sell economic tax credit</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromEconomicTaxCreditAnnual" xlink:label="cli_ProceedsFromEconomicTaxCreditAnnual" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromEconomicTaxCreditAnnual" xlink:to="cli_ProceedsFromEconomicTaxCreditAnnual_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromEconomicTaxCreditAnnual_lbl" xml:lang="en-US">Proceeds From Economic Tax Credit, Annual</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromEconomicTaxCreditAnnual_lbl" xml:lang="en-US">Proceeds From Economic Tax Credit, Annual</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromEconomicTaxCreditAnnual_lbl" xml:lang="en-US">Annual proceeds from economic tax credit</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromEconomicTaxCreditTotal" xlink:label="cli_ProceedsFromEconomicTaxCreditTotal" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromEconomicTaxCreditTotal" xlink:to="cli_ProceedsFromEconomicTaxCreditTotal_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromEconomicTaxCreditTotal_lbl" xml:lang="en-US">Proceeds From Economic Tax Credit, Total</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromEconomicTaxCreditTotal_lbl" xml:lang="en-US">Proceeds From Economic Tax Credit, Total</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromEconomicTaxCreditTotal_lbl" xml:lang="en-US">Total proceeds from economic tax credit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable" xlink:to="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipByIncomeStatementLocationByDerivativeInstrumentRiskTable_lbl" xml:lang="en-US">Derivative Instruments, Gain (Loss) [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeInstrumentsGainLossLineItems" xlink:to="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeInstrumentsGainLossLineItems_lbl" xml:lang="en-US">Derivative Instruments, Gain (Loss) [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeLiabilityNotionalAmount" xlink:label="us-gaap_DerivativeLiabilityNotionalAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeLiabilityNotionalAmount" xlink:to="us-gaap_DerivativeLiabilityNotionalAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeLiabilityNotionalAmount_lbl" xml:lang="en-US">Derivative Liability, Notional Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeLiabilityNotionalAmount_lbl" xml:lang="en-US">Derivative notional amount</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths_lbl" xml:lang="en-US">Estimated additional amount to be reclassified to interest expense</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeFairValueOfDerivativeLiability" xlink:to="us-gaap_DerivativeFairValueOfDerivativeLiability_lbl" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeFairValueOfDerivativeLiability_lbl" xml:lang="en-US">Net liability</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="invest_DerivativeNotionalAmount_lbl" xml:lang="en-US">Derivative, Notional Amount</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet" xlink:label="us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_lbl" xml:lang="en-US">Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_lbl" xml:lang="en-US">Amount of Gain or (Loss) Recognized in Income on Derivative (Reclassification for Forecasted Transactions No Longer Probable of Occurring)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DerivativeInstrumentsGainLossRecognizedInIncomeIneffectivePortionAndAmountExcludedFromEffectivenessTestingNet_lbl" xml:lang="en-US">Reclassification of a gain</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue" xlink:to="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue_lbl" xml:lang="en-US">Derivative, Net Liability Position, Aggregate Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeNetLiabilityPositionAggregateFairValue_lbl" xml:lang="en-US">Derivatives, Net liability position</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CollateralAlreadyPostedAggregateFairValue" xlink:label="us-gaap_CollateralAlreadyPostedAggregateFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CollateralAlreadyPostedAggregateFairValue" xlink:to="us-gaap_CollateralAlreadyPostedAggregateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CollateralAlreadyPostedAggregateFairValue_lbl" xml:lang="en-US">Collateral Already Posted, Aggregate Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CollateralAlreadyPostedAggregateFairValue_lbl" xml:lang="en-US">Collateral for fair value of assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCostsLeasingGross" xlink:label="us-gaap_DeferredCostsLeasingGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCostsLeasingGross" xlink:to="us-gaap_DeferredCostsLeasingGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredCostsLeasingGross_lbl" xml:lang="en-US">Deferred Costs, Leasing, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredCostsLeasingGross_lbl" xml:lang="en-US">Deferred leasing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredFinanceCostsGross" xlink:label="us-gaap_DeferredFinanceCostsGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredFinanceCostsGross" xlink:to="us-gaap_DeferredFinanceCostsGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredFinanceCostsGross_lbl" xml:lang="en-US">Deferred Finance Costs, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredFinanceCostsGross_lbl" xml:lang="en-US">Deferred financing costs - unsecured revolving credit facility</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredCostsGross" xlink:label="cli_DeferredCostsGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredCostsGross" xlink:to="cli_DeferredCostsGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredCostsGross_lbl" xml:lang="en-US">Deferred Costs, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredCostsGross_lbl" xml:lang="en-US">Deferred Costs, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="cli_DeferredCostsGross_lbl" xml:lang="en-US">Deferred charges, net</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AccumulatedAmortizationLeasingAndFinancingCosts" xlink:label="cli_AccumulatedAmortizationLeasingAndFinancingCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AccumulatedAmortizationLeasingAndFinancingCosts" xlink:to="cli_AccumulatedAmortizationLeasingAndFinancingCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AccumulatedAmortizationLeasingAndFinancingCosts_lbl" xml:lang="en-US">Accumulated Amortization Leasing And Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AccumulatedAmortizationLeasingAndFinancingCosts_lbl" xml:lang="en-US">Accumulated Amortization Leasing And Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_AccumulatedAmortizationLeasingAndFinancingCosts_lbl" xml:lang="en-US">Accumulated amortization</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCosts" xlink:label="us-gaap_DeferredCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCosts" xlink:to="us-gaap_DeferredCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredCosts_lbl" xml:lang="en-US">Deferred charges, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DeferredCosts_lbl" xml:lang="en-US">Deferred charges, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:to="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xml:lang="en-US">Loans and Leases Receivable, Net Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xml:lang="en-US">Notes receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases" xlink:label="us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases" xlink:to="us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases_lbl" xml:lang="en-US">Finite-Lived Intangible Asset, Acquired-in-Place Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_FiniteLivedIntangibleAssetAcquiredInPlaceLeases_lbl" xml:lang="en-US">In-place lease values, related intangibles and other assets, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US">Business Acquisition, Purchase Price Allocation, Goodwill Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US">Goodwill</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsRightOfUse" xlink:label="cli_AssetsRightOfUse" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsRightOfUse" xlink:to="cli_AssetsRightOfUse_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsRightOfUse_lbl" xml:lang="en-US">Assets Right-Of-Use</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsRightOfUse_lbl" xml:lang="en-US">Assets Right-Of-Use</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsRightOfUse_lbl" xml:lang="en-US">Right of use assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssets" xlink:label="us-gaap_PrepaidExpenseAndOtherAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PrepaidExpenseAndOtherAssets" xlink:to="us-gaap_PrepaidExpenseAndOtherAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PrepaidExpenseAndOtherAssets_lbl" xml:lang="en-US">Prepaid expenses and other assets, net</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AssetsRightOfUseLiability" xlink:label="cli_AssetsRightOfUseLiability" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AssetsRightOfUseLiability" xlink:to="cli_AssetsRightOfUseLiability_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AssetsRightOfUseLiability_lbl" xml:lang="en-US">Assets Right Of Use, Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AssetsRightOfUseLiability_lbl" xml:lang="en-US">Assets Right Of Use, Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AssetsRightOfUseLiability_lbl" xml:lang="en-US">Liability</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="us-gaap_DerivativeAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeAssets" xlink:to="us-gaap_DerivativeAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeAssets_lbl" xml:lang="en-US">Derivative Asset</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeAssets_lbl" xml:lang="en-US">Asset Derivatives</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_lbl" xml:lang="en-US">Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OtherComprehensiveIncomeUnrealizedGainLossOnDerivativesArisingDuringPeriodBeforeTax_lbl" xml:lang="en-US">Amount of Gain or (Loss) Recognized in OCI on Derivative</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet" xlink:label="us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_lbl" xml:lang="en-US">Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeEffectivePortionNet_lbl" xml:lang="en-US">Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SecurityDeposit" xlink:label="us-gaap_SecurityDeposit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SecurityDeposit" xlink:to="us-gaap_SecurityDeposit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SecurityDeposit_lbl" xml:lang="en-US">Security Deposit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SecurityDeposit_lbl" xml:lang="en-US">Security deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EscrowDeposit" xlink:label="us-gaap_EscrowDeposit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EscrowDeposit" xlink:to="us-gaap_EscrowDeposit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EscrowDeposit_lbl" xml:lang="en-US">Escrow Deposit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EscrowDeposit_lbl" xml:lang="en-US">Escrow and other reserve funds</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentUnamortizedDiscount" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentUnamortizedDiscount" xlink:to="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xml:lang="en-US">Debt Instrument, Unamortized Discount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xml:lang="en-US">Adjustment for unamortized debt discount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentUnamortizedDiscount_lbl" xml:lang="en-US">Adjustment for unamortized debt discount</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnamortizedDeferredFinancingCosts" xlink:label="cli_UnamortizedDeferredFinancingCosts" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnamortizedDeferredFinancingCosts" xlink:to="cli_UnamortizedDeferredFinancingCosts_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnamortizedDeferredFinancingCosts_lbl" xml:lang="en-US">Unamortized Deferred Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnamortizedDeferredFinancingCosts_lbl" xml:lang="en-US">Unamortized Deferred Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_UnamortizedDeferredFinancingCosts_lbl" xml:lang="en-US">Unamortized deferred financing costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnamortizedDeferredFinancingCosts_lbl" xml:lang="en-US">Unamortized deferred financing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongTermDebt" xlink:label="us-gaap_LongTermDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebt" xlink:to="us-gaap_LongTermDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebt_lbl" xml:lang="en-US">Long-term Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebt_lbl" xml:lang="en-US">Total indebtedness</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LongTermDebt_lbl" xml:lang="en-US">Total senior unsecured notes, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="us-gaap_LineOfCreditFacilityTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityTable" xlink:to="us-gaap_LineOfCreditFacilityTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityTable_lbl" xml:lang="en-US">Line of Credit Facility [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityLineItems" xlink:label="us-gaap_LineOfCreditFacilityLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityLineItems" xlink:to="us-gaap_LineOfCreditFacilityLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityLineItems_lbl" xml:lang="en-US">Line of Credit Facility [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_UnsecuredLongTermDebt" xlink:label="us-gaap_UnsecuredLongTermDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnsecuredLongTermDebt" xlink:to="us-gaap_UnsecuredLongTermDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UnsecuredLongTermDebt_lbl" xml:lang="en-US">Unsecured Long-term Debt, Noncurrent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_UnsecuredLongTermDebt_lbl" xml:lang="en-US">Unsecured term loan, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DerivativeAverageVariableInterestRate" xlink:label="us-gaap_DerivativeAverageVariableInterestRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeAverageVariableInterestRate" xlink:to="us-gaap_DerivativeAverageVariableInterestRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeAverageVariableInterestRate_lbl" xml:lang="en-US">Derivative, Average Variable Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeAverageVariableInterestRate_lbl" xml:lang="en-US">Interest rate swap</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LineOfCreditFacilityLendingInstitutionsNumber" xlink:label="cli_LineOfCreditFacilityLendingInstitutionsNumber" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LineOfCreditFacilityLendingInstitutionsNumber" xlink:to="cli_LineOfCreditFacilityLendingInstitutionsNumber_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LineOfCreditFacilityLendingInstitutionsNumber_lbl" xml:lang="en-US">Line of Credit Facility, Lending Institutions Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LineOfCreditFacilityLendingInstitutionsNumber_lbl" xml:lang="en-US">Line of Credit Facility, Lending Institutions Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LineOfCreditFacilityLendingInstitutionsNumber_lbl" xml:lang="en-US">Number of lending institutions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityExpirationDate1" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityExpirationDate1" xlink:to="us-gaap_LineOfCreditFacilityExpirationDate1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1_lbl" xml:lang="en-US">Line of Credit Facility, Expiration Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityExpirationDate1_lbl" xml:lang="en-US">Credit facility maturity date</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LineOfCreditFacilityExtensionPeriod" xlink:label="cli_LineOfCreditFacilityExtensionPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LineOfCreditFacilityExtensionPeriod" xlink:to="cli_LineOfCreditFacilityExtensionPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LineOfCreditFacilityExtensionPeriod_lbl" xml:lang="en-US">Line Of Credit Facility Extension Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LineOfCreditFacilityExtensionPeriod_lbl" xml:lang="en-US">Line Of Credit Facility Extension Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LineOfCreditFacilityExtensionPeriod_lbl" xml:lang="en-US">Credit facility, extension period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentCovenantComplianceLeverageRatio" xlink:label="cli_DebtInstrumentCovenantComplianceLeverageRatio" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentCovenantComplianceLeverageRatio" xlink:to="cli_DebtInstrumentCovenantComplianceLeverageRatio_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentCovenantComplianceLeverageRatio_lbl" xml:lang="en-US">Debt Instrument Covenant Compliance, Leverage Ratio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentCovenantComplianceLeverageRatio_lbl" xml:lang="en-US">Debt Instrument Covenant Compliance, Leverage Ratio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentCovenantComplianceLeverageRatio_lbl" xml:lang="en-US">Leverage ratio</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityCovenantTerms" xlink:label="us-gaap_LineOfCreditFacilityCovenantTerms" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityCovenantTerms" xlink:to="us-gaap_LineOfCreditFacilityCovenantTerms_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityCovenantTerms_lbl" xml:lang="en-US">Line of Credit Facility, Covenant Terms</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LineOfCreditFacilityCovenantTerms_lbl" xml:lang="en-US">Terms of the unsecured facility</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityDividendRestrictions" xlink:label="us-gaap_LineOfCreditFacilityDividendRestrictions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityDividendRestrictions" xlink:to="us-gaap_LineOfCreditFacilityDividendRestrictions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityDividendRestrictions_lbl" xml:lang="en-US">Line of Credit Facility, Dividend Restrictions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LineOfCreditFacilityDividendRestrictions_lbl" xml:lang="en-US">Terms of dividend restriction</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="us-gaap_DebtInstrumentTerm" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTerm" xlink:to="us-gaap_DebtInstrumentTerm_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xml:lang="en-US">Debt Instrument, Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xml:lang="en-US">Loan period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed" xlink:label="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed" xlink:to="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed_lbl" xml:lang="en-US">Debt Instrument, Initial Term Commitment Percentage Borrowed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed_lbl" xml:lang="en-US">Debt Instrument, Initial Term Commitment Percentage Borrowed</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentInitialTermCommitmentPercentageBorrowed_lbl" xml:lang="en-US">Minimum percentage of initial borrowing</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentTermCommitmentFeePerAnnum" xlink:label="cli_DebtInstrumentTermCommitmentFeePerAnnum" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentTermCommitmentFeePerAnnum" xlink:to="cli_DebtInstrumentTermCommitmentFeePerAnnum_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentTermCommitmentFeePerAnnum_lbl" xml:lang="en-US">Debt Instrument, Term Commitment Fee Per Annum</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentTermCommitmentFeePerAnnum_lbl" xml:lang="en-US">Debt Instrument, Term Commitment Fee Per Annum</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentTermCommitmentFeePerAnnum_lbl" xml:lang="en-US">Term commitment fee percent</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate" xlink:label="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate" xlink:to="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate_lbl" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity That May Be Elected After Effective Loan Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate_lbl" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity That May Be Elected After Effective Loan Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LineOfCreditFacilityMaximumBorrowingCapacityThatMayBeElectedAfterEffectiveLoanDate_lbl" xml:lang="en-US">Maximum loan increase that may be requested</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeePercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityCommitmentFeePercentage" xlink:to="us-gaap_LineOfCreditFacilityCommitmentFeePercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeePercentage_lbl" xml:lang="en-US">Line of Credit Facility, Basis Points of Facility Fees</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeePercentage_lbl" xml:lang="en-US">Facility fee basis points</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LineOfCreditFacilityCommitmentFeePercentage_lbl" xml:lang="en-US">Facility Fee Basis Points</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtInstrumentExtensionFeeAmount" xlink:label="cli_DebtInstrumentExtensionFeeAmount" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtInstrumentExtensionFeeAmount" xlink:to="cli_DebtInstrumentExtensionFeeAmount_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtInstrumentExtensionFeeAmount_lbl" xml:lang="en-US">Debt Instrument, Extension Fee Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtInstrumentExtensionFeeAmount_lbl" xml:lang="en-US">Debt Instrument, Extension Fee Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DebtInstrumentExtensionFeeAmount_lbl" xml:lang="en-US">Extension fee amount</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_GainLossOnEarlyTerminationOfDebt" xlink:label="cli_GainLossOnEarlyTerminationOfDebt" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_GainLossOnEarlyTerminationOfDebt" xlink:to="cli_GainLossOnEarlyTerminationOfDebt_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_GainLossOnEarlyTerminationOfDebt_lbl" xml:lang="en-US">Gain (Loss) on Early Termination of Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_GainLossOnEarlyTerminationOfDebt_lbl" xml:lang="en-US">Gain (Loss) on Early Termination of Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_GainLossOnEarlyTerminationOfDebt_lbl" xml:lang="en-US">Gain on early termination</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentCreditRating" xlink:label="us-gaap_DebtInstrumentCreditRating" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentCreditRating" xlink:to="us-gaap_DebtInstrumentCreditRating_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentCreditRating_lbl" xml:lang="en-US">Debt Instrument, Credit Rating</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentCreditRating_lbl" xml:lang="en-US">Unsecured Debt Ratings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xml:lang="en-US">Debt Instrument [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="us-gaap_DebtInstrumentNameDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US">Debt Instrument Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US">Debt Instrument, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember" xlink:label="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember" xlink:to="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember_lbl" xml:lang="en-US">Revolving Credit Facility and Other Variable Rate Mortgage Debt [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember_lbl" xml:lang="en-US">Revolving Credit Facility And Other Variable Rate Mortgage Debt [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RevolvingCreditFacilityAndOtherVariableRateMortgageDebtMember_lbl" xml:lang="en-US">Revolving Credit Facility Borrowing And Other Variable Rate Mortgage Debt [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_FixedRateDebtAndOtherObligationsMember" xlink:label="cli_FixedRateDebtAndOtherObligationsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_FixedRateDebtAndOtherObligationsMember" xlink:to="cli_FixedRateDebtAndOtherObligationsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FixedRateDebtAndOtherObligationsMember_lbl" xml:lang="en-US">Fixed Rate Debt and Other Obligations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FixedRateDebtAndOtherObligationsMember_lbl" xml:lang="en-US">Fixed Rate Debt And Other Obligations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FixedRateDebtAndOtherObligationsMember_lbl" xml:lang="en-US">Fixed Rate Debt And Other Obligations [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfPropertiesWithEncumberedCompanyMortgages" xlink:label="cli_NumberOfPropertiesWithEncumberedCompanyMortgages" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfPropertiesWithEncumberedCompanyMortgages" xlink:to="cli_NumberOfPropertiesWithEncumberedCompanyMortgages_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfPropertiesWithEncumberedCompanyMortgages_lbl" xml:lang="en-US">Number Of Properties With Encumbered Company Mortgages</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfPropertiesWithEncumberedCompanyMortgages_lbl" xml:lang="en-US">Number Of Properties With Encumbered Company Mortgages</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfPropertiesWithEncumberedCompanyMortgages_lbl" xml:lang="en-US">Number of properties with encumbered company mortgages</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MortgagePropertyCarryingValue" xlink:label="cli_MortgagePropertyCarryingValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MortgagePropertyCarryingValue" xlink:to="cli_MortgagePropertyCarryingValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MortgagePropertyCarryingValue_lbl" xml:lang="en-US">Carrying Value of the Mortgaged Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MortgagePropertyCarryingValue_lbl" xml:lang="en-US">Mortgage Property, Carrying Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MortgagePropertyCarryingValue_lbl" xml:lang="en-US">Carrying value of encumbered properties</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestPaid" xlink:label="us-gaap_InterestPaid" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPaid" xlink:to="us-gaap_InterestPaid_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestPaid_lbl" xml:lang="en-US">Interest Paid</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestPaid_lbl" xml:lang="en-US">Cash paid for interest</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestCostsCapitalized" xlink:label="us-gaap_InterestCostsCapitalized" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestCostsCapitalized" xlink:to="us-gaap_InterestCostsCapitalized_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestCostsCapitalized_lbl" xml:lang="en-US">Interest Costs, Capitalized During Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestCostsCapitalized_lbl" xml:lang="en-US">Interest capitalized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LongtermDebtWeightedAverageInterestRate" xlink:label="us-gaap_LongtermDebtWeightedAverageInterestRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongtermDebtWeightedAverageInterestRate" xlink:to="us-gaap_LongtermDebtWeightedAverageInterestRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongtermDebtWeightedAverageInterestRate_lbl" xml:lang="en-US">Long-term Debt, Weighted Average Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongtermDebtWeightedAverageInterestRate_lbl" xml:lang="en-US">Total indebtedness, weighted average interest rate</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PortImperialFourFiveHotelMember" xlink:label="cli_PortImperialFourFiveHotelMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PortImperialFourFiveHotelMember" xlink:to="cli_PortImperialFourFiveHotelMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PortImperialFourFiveHotelMember_lbl" xml:lang="en-US">Port Imperial Four Five Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PortImperialFourFiveHotelMember_lbl" xml:lang="en-US">Port Imperial Four Five Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PortImperialFourFiveHotelMember_lbl" xml:lang="en-US">Port Imperial 4/5 Hotel [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SecuredDebtNameOfProperty" xlink:label="cli_SecuredDebtNameOfProperty" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SecuredDebtNameOfProperty" xlink:to="cli_SecuredDebtNameOfProperty_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SecuredDebtNameOfProperty_lbl" xml:lang="en-US">Secured Debt, Name of the Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SecuredDebtNameOfProperty_lbl" xml:lang="en-US">Secured Debt, Name of the Property</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SecuredDebtNameOfProperty_lbl" xml:lang="en-US">Property Name</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SecuredDebtLendingInstitution" xlink:label="cli_SecuredDebtLendingInstitution" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SecuredDebtLendingInstitution" xlink:to="cli_SecuredDebtLendingInstitution_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SecuredDebtLendingInstitution_lbl" xml:lang="en-US">Secured Debt, Lending Institution</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SecuredDebtLendingInstitution_lbl" xml:lang="en-US">Secured Debt, Lending Institution</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SecuredDebtLendingInstitution_lbl" xml:lang="en-US">Lender</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DebtLoansPayableAndOtherObligationsNet" xlink:label="cli_DebtLoansPayableAndOtherObligationsNet" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DebtLoansPayableAndOtherObligationsNet" xlink:to="cli_DebtLoansPayableAndOtherObligationsNet_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DebtLoansPayableAndOtherObligationsNet_lbl" xml:lang="en-US">Debt, Loans Payable, And Other Obligations, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DebtLoansPayableAndOtherObligationsNet_lbl" xml:lang="en-US">Debt, Loans Payable, And Other Obligations, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="cli_DebtLoansPayableAndOtherObligationsNet_lbl" xml:lang="en-US">Total mortgages, loans payable and other obligations, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable" xlink:to="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfDeferredCompensationArrangementWithIndividualPostretirementBenefitsTable_lbl" xml:lang="en-US">Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualPostretirementBenefitsLineItems_lbl" xml:lang="en-US">Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate" xlink:label="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate" xlink:to="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate_lbl" xml:lang="en-US">Savings Retirement Plan Employee Minimum Subscription Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate_lbl" xml:lang="en-US">Savings Retirement Plan Employee Minimum Subscription Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SavingsRetirementPlanEmployeeMinimumSubscriptionRate_lbl" xml:lang="en-US">Minimum employee subscription rate, percentage of compensation</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate" xlink:label="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate" xlink:to="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate_lbl" xml:lang="en-US">Savings Retirement Plan Employee Maximum Subscription Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate_lbl" xml:lang="en-US">Savings Retirement Plan Employee Maximum Subscription Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SavingsRetirementPlanEmployeeMaximumSubscriptionRate_lbl" xml:lang="en-US">Maximum employee subscription rate, percentage of compensation</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_EmployeePreTaxContributionsVestedPercent" xlink:label="cli_EmployeePreTaxContributionsVestedPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_EmployeePreTaxContributionsVestedPercent" xlink:to="cli_EmployeePreTaxContributionsVestedPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_EmployeePreTaxContributionsVestedPercent_lbl" xml:lang="en-US">Employee pre-tax contributions vested percent.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_EmployeePreTaxContributionsVestedPercent_lbl" xml:lang="en-US">Employee Pre Tax Contributions Vested Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_EmployeePreTaxContributionsVestedPercent_lbl" xml:lang="en-US">Employee pre-tax contributions vested percentage</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SavingsRetirementPlanVestingPeriod" xlink:label="cli_SavingsRetirementPlanVestingPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SavingsRetirementPlanVestingPeriod" xlink:to="cli_SavingsRetirementPlanVestingPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SavingsRetirementPlanVestingPeriod_lbl" xml:lang="en-US">Savings Retirement Plan Vesting Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SavingsRetirementPlanVestingPeriod_lbl" xml:lang="en-US">Savings Retirement Plan Vesting Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SavingsRetirementPlanVestingPeriod_lbl" xml:lang="en-US">Employer contribution vesting period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_VestingRate" xlink:label="cli_VestingRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_VestingRate" xlink:to="cli_VestingRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_VestingRate_lbl" xml:lang="en-US">Vesting rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_VestingRate_lbl" xml:lang="en-US">Vesting Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_VestingRate_lbl" xml:lang="en-US">Vesting rate</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentVestedAfterTotalServicePeriod" xlink:label="cli_PercentVestedAfterTotalServicePeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentVestedAfterTotalServicePeriod" xlink:to="cli_PercentVestedAfterTotalServicePeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentVestedAfterTotalServicePeriod_lbl" xml:lang="en-US">Percent vested after total service period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentVestedAfterTotalServicePeriod_lbl" xml:lang="en-US">Percent Vested After Total Service Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentVestedAfterTotalServicePeriod_lbl" xml:lang="en-US">Percentage vested after total service period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SavingsRetirementPlanVestingRights" xlink:label="cli_SavingsRetirementPlanVestingRights" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SavingsRetirementPlanVestingRights" xlink:to="cli_SavingsRetirementPlanVestingRights_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SavingsRetirementPlanVestingRights_lbl" xml:lang="en-US">Savings Retirement Plan Vesting Rights</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SavingsRetirementPlanVestingRights_lbl" xml:lang="en-US">Savings Retirement Plan Vesting Rights</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SavingsRetirementPlanVestingRights_lbl" xml:lang="en-US">Employees' vesting rights</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeBenefitsAndShareBasedCompensation" xlink:label="us-gaap_EmployeeBenefitsAndShareBasedCompensation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeBenefitsAndShareBasedCompensation" xlink:to="us-gaap_EmployeeBenefitsAndShareBasedCompensation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeBenefitsAndShareBasedCompensation_lbl" xml:lang="en-US">Employee Benefits and Share-based Compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeBenefitsAndShareBasedCompensation_lbl" xml:lang="en-US">Expenses for employee benefit plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesTable_lbl" xml:lang="en-US">Fair Value Measurement Inputs and Valuation Techniques [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisValuationTechniquesLineItems_lbl" xml:lang="en-US">Fair Value Measurement Inputs and Valuation Techniques [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="us-gaap_DebtInstrumentFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentFairValue" xlink:to="us-gaap_DebtInstrumentFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xml:lang="en-US">Debt Instrument, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xml:lang="en-US">Fair value of Company's long-term debt</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_HarborsideFinancialCenterPlazaFouraMember" xlink:label="cli_HarborsideFinancialCenterPlazaFouraMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_HarborsideFinancialCenterPlazaFouraMember" xlink:to="cli_HarborsideFinancialCenterPlazaFouraMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_HarborsideFinancialCenterPlazaFouraMember_lbl" xml:lang="en-US">Harborside Financial Center Plaza 4-A [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_HarborsideFinancialCenterPlazaFouraMember_lbl" xml:lang="en-US">Harborside Financial Center Plaza Foura [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_HarborsideFinancialCenterPlazaFouraMember_lbl" xml:lang="en-US">Harborside Plaza 4-A [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_HarborsideFinancialCenterPlazaFiveMember" xlink:label="cli_HarborsideFinancialCenterPlazaFiveMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_HarborsideFinancialCenterPlazaFiveMember" xlink:to="cli_HarborsideFinancialCenterPlazaFiveMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_HarborsideFinancialCenterPlazaFiveMember_lbl" xml:lang="en-US">Harborside Financial Center Plaza 5 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_HarborsideFinancialCenterPlazaFiveMember_lbl" xml:lang="en-US">Harborside Financial Center Plaza Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_HarborsideFinancialCenterPlazaFiveMember_lbl" xml:lang="en-US">Harborside Plaza 5 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PortImperialFourAndFiveGarageDevelopmentMember" xlink:label="cli_PortImperialFourAndFiveGarageDevelopmentMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PortImperialFourAndFiveGarageDevelopmentMember" xlink:to="cli_PortImperialFourAndFiveGarageDevelopmentMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PortImperialFourAndFiveGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial 4/5 Garage Development [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PortImperialFourAndFiveGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial Four And Five Garage Development [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PortImperialFourAndFiveGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial South 4/5 Garage [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PortImperialSouthOneThirdGarageDevelopmentMember" xlink:label="cli_PortImperialSouthOneThirdGarageDevelopmentMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PortImperialSouthOneThirdGarageDevelopmentMember" xlink:to="cli_PortImperialSouthOneThirdGarageDevelopmentMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PortImperialSouthOneThirdGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial South One Third Garage Development [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PortImperialSouthOneThirdGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial South One Third Garage Development [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PortImperialSouthOneThirdGarageDevelopmentMember_lbl" xml:lang="en-US">Port Imperial South 1/3 Garage [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProjectTerm" xlink:label="cli_ProjectTerm" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProjectTerm" xlink:to="cli_ProjectTerm_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProjectTerm_lbl" xml:lang="en-US">Project Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProjectTerm_lbl" xml:lang="en-US">Project Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProjectTerm_lbl" xml:lang="en-US">Project period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost" xlink:to="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost_lbl" xml:lang="en-US">Payments in Lieu of Property Tax As Percentage of Total Project Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost_lbl" xml:lang="en-US">Payments in Lieu of Property Tax As Percentage of Total Project Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfTotalProjectCost_lbl" xml:lang="en-US">Percentage of PILOT on project costs</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_EstimatedCostOfProject" xlink:label="cli_EstimatedCostOfProject" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_EstimatedCostOfProject" xlink:to="cli_EstimatedCostOfProject_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_EstimatedCostOfProject_lbl" xml:lang="en-US">Estimated Cost Of Project</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_EstimatedCostOfProject_lbl" xml:lang="en-US">Estimated Cost Of Project</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_EstimatedCostOfProject_lbl" xml:lang="en-US">Total project costs</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsInLieuOfPropertyTaxes" xlink:label="cli_PaymentsInLieuOfPropertyTaxes" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsInLieuOfPropertyTaxes" xlink:to="cli_PaymentsInLieuOfPropertyTaxes_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsInLieuOfPropertyTaxes_lbl" xml:lang="en-US">Payments In Lieu Of Property Taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsInLieuOfPropertyTaxes_lbl" xml:lang="en-US">Payments In Lieu Of Property Taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsInLieuOfPropertyTaxes_lbl" xml:lang="en-US">Payments in lieu of property taxes (PILOT)</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsInLieuOfPropertyTaxesAnnualPayment" xlink:label="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment" xlink:to="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment_lbl" xml:lang="en-US">Payments In Lieu Of Property Taxes, Annual Payment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment_lbl" xml:lang="en-US">Payments In Lieu Of Property Taxes, Annual Payment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsInLieuOfPropertyTaxesAnnualPayment_lbl" xml:lang="en-US">Annual Payments in lieu of property taxes (PILOT)</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue" xlink:to="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue_lbl" xml:lang="en-US">Payments In Lieu Of Property Tax As Percentage Based On The Land Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue_lbl" xml:lang="en-US">Payments In Lieu Of Property Tax As Percentage Based On Land Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageBasedOnLandValue_lbl" xml:lang="en-US">Percentage of taxes paid based on the land value</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualPercentageOfCostForPhaseIn" xlink:label="cli_AnnualPercentageOfCostForPhaseIn" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualPercentageOfCostForPhaseIn" xlink:to="cli_AnnualPercentageOfCostForPhaseIn_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualPercentageOfCostForPhaseIn_lbl" xml:lang="en-US">Annual Percentage Of Cost For Phase In</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualPercentageOfCostForPhaseIn_lbl" xml:lang="en-US">Annual Percentage Of Cost For Phase In</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualPercentageOfCostForPhaseIn_lbl" xml:lang="en-US">Annual percentage of cost for phase in</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues" xlink:to="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues_lbl" xml:lang="en-US">Payments In Lieu Of Property Tax As Percentage Of Gross Revenues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues_lbl" xml:lang="en-US">Payments In Lieu Of Property Tax As Percentage Of Gross Revenues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PaymentsInLieuOfPropertyTaxAsPercentageOfGrossRevenues_lbl" xml:lang="en-US">Percentage of PILOT on gross revenues</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionTable" xlink:label="us-gaap_LesseeLeaseDescriptionTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeLeaseDescriptionTable" xlink:to="us-gaap_LesseeLeaseDescriptionTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LesseeLeaseDescriptionTable_lbl" xml:lang="en-US">Lessee, Lease, Description [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeLeaseDescriptionLineItems" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeLeaseDescriptionLineItems" xlink:to="us-gaap_LesseeLeaseDescriptionLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LesseeLeaseDescriptionLineItems_lbl" xml:lang="en-US">Lessee, Lease, Description [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OperatingLeaseExpenseIncludingSubleaseRentals" xlink:label="cli_OperatingLeaseExpenseIncludingSubleaseRentals" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OperatingLeaseExpenseIncludingSubleaseRentals" xlink:to="cli_OperatingLeaseExpenseIncludingSubleaseRentals_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OperatingLeaseExpenseIncludingSubleaseRentals_lbl" xml:lang="en-US">Operating Lease, Expense, Including Sublease Rentals</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OperatingLeaseExpenseIncludingSubleaseRentals_lbl" xml:lang="en-US">Operating Lease, Expense, Including Sublease Rentals</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_OperatingLeaseExpenseIncludingSubleaseRentals_lbl" xml:lang="en-US">Ground lease expense incurred</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="us-gaap_OperatingLeaseLiability" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeaseLiability" xlink:to="us-gaap_OperatingLeaseLiability_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xml:lang="en-US">Operating Lease, Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeaseLiability_lbl" xml:lang="en-US">Operating lease</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OperatingLeaseNumberOfUnits" xlink:label="cli_OperatingLeaseNumberOfUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OperatingLeaseNumberOfUnits" xlink:to="cli_OperatingLeaseNumberOfUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OperatingLeaseNumberOfUnits_lbl" xml:lang="en-US">Operating Lease, Number of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OperatingLeaseNumberOfUnits_lbl" xml:lang="en-US">Operating Lease, Number of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_OperatingLeaseNumberOfUnits_lbl" xml:lang="en-US">Number of ground leases</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeFinanceLeaseTermOfContract1" xlink:label="us-gaap_LesseeFinanceLeaseTermOfContract1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeFinanceLeaseTermOfContract1" xlink:to="us-gaap_LesseeFinanceLeaseTermOfContract1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LesseeFinanceLeaseTermOfContract1_lbl" xml:lang="en-US">Lessee, Finance Lease, Term of Contract</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LesseeFinanceLeaseTermOfContract1_lbl" xml:lang="en-US">Term of lease contract</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LesseeOperatingLeaseDiscountRate" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LesseeOperatingLeaseDiscountRate" xlink:to="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xml:lang="en-US">Lessee, Operating Lease, Discount Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LesseeOperatingLeaseDiscountRate_lbl" xml:lang="en-US">Borrowing rate</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PropertyNetBookValue" xlink:label="cli_PropertyNetBookValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PropertyNetBookValue" xlink:to="cli_PropertyNetBookValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PropertyNetBookValue_lbl" xml:lang="en-US">Property Net Book Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PropertyNetBookValue_lbl" xml:lang="en-US">Property Net Book Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PropertyNetBookValue_lbl" xml:lang="en-US">Properties aggregate net book value</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeliveryDateOfConstructedBuilding" xlink:label="cli_DeliveryDateOfConstructedBuilding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeliveryDateOfConstructedBuilding" xlink:to="cli_DeliveryDateOfConstructedBuilding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeliveryDateOfConstructedBuilding_lbl" xml:lang="en-US">Delivery date of constructed building</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeliveryDateOfConstructedBuilding_lbl" xml:lang="en-US">Delivery Date Of Constructed Building</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DeliveryDateOfConstructedBuilding_lbl" xml:lang="en-US">Delivery date to tenant</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AmountToFund" xlink:label="cli_AmountToFund" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AmountToFund" xlink:to="cli_AmountToFund_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AmountToFund_lbl" xml:lang="en-US">Amount To Fund</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AmountToFund_lbl" xml:lang="en-US">Amount To Fund</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AmountToFund_lbl" xml:lang="en-US">Amount to fund</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ChangesInExecutiveOfficersTable" xlink:label="cli_ChangesInExecutiveOfficersTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ChangesInExecutiveOfficersTable" xlink:to="cli_ChangesInExecutiveOfficersTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ChangesInExecutiveOfficersTable_lbl" xml:lang="en-US">Changes In Executive Officers [Table]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ChangesInExecutiveOfficersTable_lbl" xml:lang="en-US">Changes In Executive Officers [Table]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ChangesInExecutiveOfficersLineItems" xlink:label="cli_ChangesInExecutiveOfficersLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ChangesInExecutiveOfficersLineItems" xlink:to="cli_ChangesInExecutiveOfficersLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ChangesInExecutiveOfficersLineItems_lbl" xml:lang="en-US">Changes In Executive Officers [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ChangesInExecutiveOfficersLineItems_lbl" xml:lang="en-US">Changes In Executive Officers [Line Items]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualBaseSalary" xlink:label="cli_AnnualBaseSalary" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualBaseSalary" xlink:to="cli_AnnualBaseSalary_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualBaseSalary_lbl" xml:lang="en-US">Annual Base Salary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualBaseSalary_lbl" xml:lang="en-US">Annual Base Salary</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualBaseSalary_lbl" xml:lang="en-US">Annual base salary</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualBonusOpportunityPercentage" xlink:label="cli_AnnualBonusOpportunityPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualBonusOpportunityPercentage" xlink:to="cli_AnnualBonusOpportunityPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualBonusOpportunityPercentage_lbl" xml:lang="en-US">Annual Bonus Opportunity Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualBonusOpportunityPercentage_lbl" xml:lang="en-US">Annual Bonus Opportunity Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualBonusOpportunityPercentage_lbl" xml:lang="en-US">Annual bonus opportunity percentage</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualBonusOpportunityThresholdPercentage" xlink:label="cli_AnnualBonusOpportunityThresholdPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualBonusOpportunityThresholdPercentage" xlink:to="cli_AnnualBonusOpportunityThresholdPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualBonusOpportunityThresholdPercentage_lbl" xml:lang="en-US">Annual Bonus Opportunity Threshold Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualBonusOpportunityThresholdPercentage_lbl" xml:lang="en-US">Annual Bonus Opportunity Threshold Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualBonusOpportunityThresholdPercentage_lbl" xml:lang="en-US">Annual bonus opportunity threshold percentage</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US">Shares Under Options - Granted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US">Shares granted</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xml:lang="en-US">Exercisable period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_lbl" xml:lang="en-US">Expiration period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PeriodForContinuationOfHealthInsurance" xlink:label="cli_PeriodForContinuationOfHealthInsurance" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PeriodForContinuationOfHealthInsurance" xlink:to="cli_PeriodForContinuationOfHealthInsurance_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PeriodForContinuationOfHealthInsurance_lbl" xml:lang="en-US">Period For Continuation Of Health Insurance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PeriodForContinuationOfHealthInsurance_lbl" xml:lang="en-US">Period For Continuation Of Health Insurance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PeriodForContinuationOfHealthInsurance_lbl" xml:lang="en-US">Period for continuation of health insurance</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PropertyLockUpsExpiredMember" xlink:label="cli_PropertyLockUpsExpiredMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PropertyLockUpsExpiredMember" xlink:to="cli_PropertyLockUpsExpiredMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PropertyLockUpsExpiredMember_lbl" xml:lang="en-US">Property Lock-Ups Expired [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PropertyLockUpsExpiredMember_lbl" xml:lang="en-US">Property Lock Ups Expired [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PropertyLockUpsExpiredMember_lbl" xml:lang="en-US">Property Lock-Ups Expired [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProceedsFromPrepaidNotesReceivable" xlink:label="cli_ProceedsFromPrepaidNotesReceivable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProceedsFromPrepaidNotesReceivable" xlink:to="cli_ProceedsFromPrepaidNotesReceivable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProceedsFromPrepaidNotesReceivable_lbl" xml:lang="en-US">Proceeds From Prepaid Notes Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProceedsFromPrepaidNotesReceivable_lbl" xml:lang="en-US">Proceeds From Prepaid Notes Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProceedsFromPrepaidNotesReceivable_lbl" xml:lang="en-US">Prepayment of note receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Remainder of Fiscal Year</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsRemainderOfFiscalYear_lbl" xml:lang="en-US">April 1 through December 31, 2019</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Two Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US">2020</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Three Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US">2021</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Four Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US">2022</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due in Five Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xml:lang="en-US">2023</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments, Due Thereafter</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter_lbl" xml:lang="en-US">2024 through 2084</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Due</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDue_lbl" xml:lang="en-US">Total</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable" xlink:to="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseByMajorPropertyClassTable_lbl" xml:lang="en-US">Property Subject to or Available for Operating Lease, by Major Property Class [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis" xlink:to="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseAxis_lbl" xml:lang="en-US">Property Subject to or Available for Operating Lease [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain" xlink:to="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_lbl" xml:lang="en-US">Property Subject To Or Available For Operating Lease [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseDomain_lbl" xml:lang="en-US">Property Subject to or Available for Operating Lease [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TenantLeasesMember" xlink:label="cli_TenantLeasesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TenantLeasesMember" xlink:to="cli_TenantLeasesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TenantLeasesMember_lbl" xml:lang="en-US">Tenant Leases [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TenantLeasesMember_lbl" xml:lang="en-US">Tenant Leases [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TenantLeasesMember_lbl" xml:lang="en-US">Tenant Leases [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems" xlink:to="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertySubjectToOrAvailableForOperatingLeaseLineItems_lbl" xml:lang="en-US">Property Subject to or Available for Operating Lease [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, Remainder of Fiscal Year</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableRemainderOfFiscalYear_lbl" xml:lang="en-US">April 1 through December 31, 2019</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, in Two Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInTwoYears_lbl" xml:lang="en-US">2020</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, in Three Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInThreeYears_lbl" xml:lang="en-US">2021</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, in Four Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFourYears_lbl" xml:lang="en-US">2022</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, in Five Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableInFiveYears_lbl" xml:lang="en-US">2023</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable, Thereafter</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivableThereafter_lbl" xml:lang="en-US">2024 and thereafter</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable_lbl" xml:lang="en-US">Operating Leases, Future Minimum Payments Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsReceivable_lbl" xml:lang="en-US">Total</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LeaseExpirationDate1" xlink:label="us-gaap_LeaseExpirationDate1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseExpirationDate1" xlink:to="us-gaap_LeaseExpirationDate1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseExpirationDate1_lbl" xml:lang="en-US">Lease Expiration Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseExpirationDate1_lbl" xml:lang="en-US">Operating leases with various expiration dates through year</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LeasePeriod" xlink:label="cli_LeasePeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LeasePeriod" xlink:to="cli_LeasePeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LeasePeriod_lbl" xml:lang="en-US">Lease Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LeasePeriod_lbl" xml:lang="en-US">Lease Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LeasePeriod_lbl" xml:lang="en-US">Lease period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ContributedEquityValue" xlink:label="cli_ContributedEquityValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ContributedEquityValue" xlink:to="cli_ContributedEquityValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ContributedEquityValue_lbl" xml:lang="en-US">Contributed Equity Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ContributedEquityValue_lbl" xml:lang="en-US">Contributed Equity Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ContributedEquityValue_lbl" xml:lang="en-US">Contributed equity value</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest" xlink:label="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest" xlink:to="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Incremental Contribution Value Equity Units Limited Partnership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Incremental Contribution Value Equity Units Limited Partnership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_IncrementalContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Incremental closing payments, Limited Partnership interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PreferredUnitsContributionToObtainEquityUnits" xlink:label="cli_PreferredUnitsContributionToObtainEquityUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PreferredUnitsContributionToObtainEquityUnits" xlink:to="cli_PreferredUnitsContributionToObtainEquityUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PreferredUnitsContributionToObtainEquityUnits_lbl" xml:lang="en-US">Preferred Units, Contribution To Obtain Equity Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PreferredUnitsContributionToObtainEquityUnits_lbl" xml:lang="en-US">Preferred Units, Contribution To Obtain Equity Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PreferredUnitsContributionToObtainEquityUnits_lbl" xml:lang="en-US">Contributed amount to obtain equity units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ContributionValueEquityUnitsLimitedPartnershipInterest" xlink:label="cli_ContributionValueEquityUnitsLimitedPartnershipInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ContributionValueEquityUnitsLimitedPartnershipInterest" xlink:to="cli_ContributionValueEquityUnitsLimitedPartnershipInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Contribution Value Equity Units Limited Partnership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Contribution Value Equity Units Limited Partnership Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ContributionValueEquityUnitsLimitedPartnershipInterest_lbl" xml:lang="en-US">Contributed amount to obtain equity units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualReturnFromCashFlowOperations" xlink:label="cli_AnnualReturnFromCashFlowOperations" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualReturnFromCashFlowOperations" xlink:to="cli_AnnualReturnFromCashFlowOperations_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualReturnFromCashFlowOperations_lbl" xml:lang="en-US">Annual Return From Cash Flow Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualReturnFromCashFlowOperations_lbl" xml:lang="en-US">Annual Return From Cash Flow Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualReturnFromCashFlowOperations_lbl" xml:lang="en-US">Annual return</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualReturnOnEquityValue" xlink:label="cli_AnnualReturnOnEquityValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualReturnOnEquityValue" xlink:to="cli_AnnualReturnOnEquityValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualReturnOnEquityValue_lbl" xml:lang="en-US">Annual Return On The Equity Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualReturnOnEquityValue_lbl" xml:lang="en-US">Annual Return On The Equity Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualReturnOnEquityValue_lbl" xml:lang="en-US">Annual return on the equity value</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_AnnualReturnOnEquityValueBaseReturn" xlink:label="cli_AnnualReturnOnEquityValueBaseReturn" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_AnnualReturnOnEquityValueBaseReturn" xlink:to="cli_AnnualReturnOnEquityValueBaseReturn_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_AnnualReturnOnEquityValueBaseReturn_lbl" xml:lang="en-US">Annual Return On The Equity Value, Base Return</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_AnnualReturnOnEquityValueBaseReturn_lbl" xml:lang="en-US">Annual Return On The Equity Value, Base Return</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_AnnualReturnOnEquityValueBaseReturn_lbl" xml:lang="en-US">Base return</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProRataDistributionPercent" xlink:label="cli_ProRataDistributionPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProRataDistributionPercent" xlink:to="cli_ProRataDistributionPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProRataDistributionPercent_lbl" xml:lang="en-US">Pro Rata Distribution Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProRataDistributionPercent_lbl" xml:lang="en-US">Pro Rata Distribution Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProRataDistributionPercent_lbl" xml:lang="en-US">Pro rata distribution</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InternalRateOfReturnPercent" xlink:label="cli_InternalRateOfReturnPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InternalRateOfReturnPercent" xlink:to="cli_InternalRateOfReturnPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InternalRateOfReturnPercent_lbl" xml:lang="en-US">Internal Rate of Return Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InternalRateOfReturnPercent_lbl" xml:lang="en-US">Internal Rate of Return Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InternalRateOfReturnPercent_lbl" xml:lang="en-US">Internal rate of return</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ProRataDistributionPercentCashFlowFromCapitalEvents" xlink:label="cli_ProRataDistributionPercentCashFlowFromCapitalEvents" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ProRataDistributionPercentCashFlowFromCapitalEvents" xlink:to="cli_ProRataDistributionPercentCashFlowFromCapitalEvents_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ProRataDistributionPercentCashFlowFromCapitalEvents_lbl" xml:lang="en-US">Pro Rata Distribution Percent, Cash Flow From Capital Events</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ProRataDistributionPercentCashFlowFromCapitalEvents_lbl" xml:lang="en-US">Pro Rata Distribution Percent, Cash Flow From Capital Events</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ProRataDistributionPercentCashFlowFromCapitalEvents_lbl" xml:lang="en-US">Pro rata share</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PreferredUnitValue" xlink:label="cli_PreferredUnitValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PreferredUnitValue" xlink:to="cli_PreferredUnitValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PreferredUnitValue_lbl" xml:lang="en-US">Value of the preferred units acquired.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PreferredUnitValue_lbl" xml:lang="en-US">Preferred Unit Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PreferredUnitValue_lbl" xml:lang="en-US">Preferred unit in operating partnership</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ConvertiblePreferredUnitSharesIssuedUponConversion" xlink:label="cli_ConvertiblePreferredUnitSharesIssuedUponConversion" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ConvertiblePreferredUnitSharesIssuedUponConversion" xlink:to="cli_ConvertiblePreferredUnitSharesIssuedUponConversion_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ConvertiblePreferredUnitSharesIssuedUponConversion_lbl" xml:lang="en-US">Convertible Preferred Unit, Shares Issued Upon Conversion</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ConvertiblePreferredUnitSharesIssuedUponConversion_lbl" xml:lang="en-US">Convertible Preferred Unit, Shares Issued Upon Conversion</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ConvertiblePreferredUnitSharesIssuedUponConversion_lbl" xml:lang="en-US">Convertible preferred units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ConversionOfStockNumberOfSharesCalledByStocks" xlink:label="cli_ConversionOfStockNumberOfSharesCalledByStocks" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ConversionOfStockNumberOfSharesCalledByStocks" xlink:to="cli_ConversionOfStockNumberOfSharesCalledByStocks_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ConversionOfStockNumberOfSharesCalledByStocks_lbl" xml:lang="en-US">Conversion Of Stock, Number Of Shares Called By Stocks</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ConversionOfStockNumberOfSharesCalledByStocks_lbl" xml:lang="en-US">Conversion Of Stock, Number Of Shares Called By Stocks</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ConversionOfStockNumberOfSharesCalledByStocks_lbl" xml:lang="en-US">Shares that may be converted to common units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitDistributionsPerUnitDeclared" xlink:label="cli_CommonUnitDistributionsPerUnitDeclared" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitDistributionsPerUnitDeclared" xlink:to="cli_CommonUnitDistributionsPerUnitDeclared_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitDistributionsPerUnitDeclared_lbl" xml:lang="en-US">Common Unit Distributions Per Unit Declared</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitDistributionsPerUnitDeclared_lbl" xml:lang="en-US">Common Unit Distributions Per Unit Declared</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitDistributionsPerUnitDeclared_lbl" xml:lang="en-US">Common unit distribution per unit declared</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_CommonUnitDistributionsPerUnitDeclared_lbl" xml:lang="en-US">Distribution declared per common unit</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NoncontrollingInterestEstimatedRedemptionValue" xlink:label="cli_NoncontrollingInterestEstimatedRedemptionValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NoncontrollingInterestEstimatedRedemptionValue" xlink:to="cli_NoncontrollingInterestEstimatedRedemptionValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NoncontrollingInterestEstimatedRedemptionValue_lbl" xml:lang="en-US">Noncontrolling Interest, Estimated Redemption Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoncontrollingInterestEstimatedRedemptionValue_lbl" xml:lang="en-US">Noncontrolling Interest, Estimated Redemption Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NoncontrollingInterestEstimatedRedemptionValue_lbl" xml:lang="en-US">Estimated redemption value</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InvestedCapital" xlink:label="cli_InvestedCapital" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InvestedCapital" xlink:to="cli_InvestedCapital_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InvestedCapital_lbl" xml:lang="en-US">Invested Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InvestedCapital_lbl" xml:lang="en-US">Invested Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InvestedCapital_lbl" xml:lang="en-US">Invested capital</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TemporaryEquityStockIssuedDuringPeriodValueGross" xlink:label="cli_TemporaryEquityStockIssuedDuringPeriodValueGross" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TemporaryEquityStockIssuedDuringPeriodValueGross" xlink:to="cli_TemporaryEquityStockIssuedDuringPeriodValueGross_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TemporaryEquityStockIssuedDuringPeriodValueGross_lbl" xml:lang="en-US">Temporary Equity, Stock Issued During Period, Value, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TemporaryEquityStockIssuedDuringPeriodValueGross_lbl" xml:lang="en-US">Temporary Equity, Stock Issued During Period, Value, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TemporaryEquityStockIssuedDuringPeriodValueGross_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests Issued</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues" xlink:to="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US">Temporary Equity, Stock Issued During Period, Value, New Issues</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues_lbl" xml:lang="en-US">Net</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RedeemableNoncontrollingInterestDecreaseFromDistribution" xlink:label="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution" xlink:to="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest Decrease From Distribution</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution_lbl" xml:lang="en-US">Redeemable Noncontrolling Interest Decrease From Distribution</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_RedeemableNoncontrollingInterestDecreaseFromDistribution_lbl" xml:lang="en-US">Distributions</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DateShareRepurchaseProgramInitiation" xlink:label="cli_DateShareRepurchaseProgramInitiation" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DateShareRepurchaseProgramInitiation" xlink:to="cli_DateShareRepurchaseProgramInitiation_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DateShareRepurchaseProgramInitiation_lbl" xml:lang="en-US">Date Share Repurchase Program was initiated.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DateShareRepurchaseProgramInitiation_lbl" xml:lang="en-US">Date Share Repurchase Program Initiation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DateShareRepurchaseProgramInitiation_lbl" xml:lang="en-US">Date share repurchase program was initiated</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:to="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl" xml:lang="en-US">Stock Repurchase Program Authorized Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockRepurchaseProgramAuthorizedAmount1_lbl" xml:lang="en-US">Capacity of share repurchase program</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares" xlink:to="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xml:lang="en-US">Stock Repurchased and Retired During Period, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockRepurchasedAndRetiredDuringPeriodShares_lbl" xml:lang="en-US">Shares purchased and retired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PaymentsForRepurchaseOfEquity" xlink:label="us-gaap_PaymentsForRepurchaseOfEquity" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForRepurchaseOfEquity" xlink:to="us-gaap_PaymentsForRepurchaseOfEquity_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForRepurchaseOfEquity_lbl" xml:lang="en-US">Payments for Repurchase of Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_PaymentsForRepurchaseOfEquity_lbl" xml:lang="en-US">Aggregate cost of stock repurchased</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:to="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xml:lang="en-US">Stock Repurchase Program Remaining Authorized Repurchase Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_lbl" xml:lang="en-US">Capacity available for additional repurchase of outstanding common stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits" xlink:to="us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits_lbl" xml:lang="en-US">Proceeds from Issuance of Common Limited Partners Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfCommonLimitedPartnersUnits_lbl" xml:lang="en-US">Proceeds from sale of common units</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:to="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xml:lang="en-US">Common stock reserved for future issuance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_lbl" xml:lang="en-US">Reserved stocks for issuance</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MonthlyCashInvestmentWithoutRestrictionMaximum" xlink:label="cli_MonthlyCashInvestmentWithoutRestrictionMaximum" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MonthlyCashInvestmentWithoutRestrictionMaximum" xlink:to="cli_MonthlyCashInvestmentWithoutRestrictionMaximum_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MonthlyCashInvestmentWithoutRestrictionMaximum_lbl" xml:lang="en-US">Monthly cash investment without restriction, maximum.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MonthlyCashInvestmentWithoutRestrictionMaximum_lbl" xml:lang="en-US">Monthly Cash Investment Without Restriction Maximum</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MonthlyCashInvestmentWithoutRestrictionMaximum_lbl" xml:lang="en-US">Monthly cash investment without restriction, maximum</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:to="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_lbl" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US">Plan Name [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US">Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US">Plan Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TwoThousandThirteenIncentiveStockPlanMember" xlink:label="cli_TwoThousandThirteenIncentiveStockPlanMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TwoThousandThirteenIncentiveStockPlanMember" xlink:to="cli_TwoThousandThirteenIncentiveStockPlanMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TwoThousandThirteenIncentiveStockPlanMember_lbl" xml:lang="en-US">2013 Incentive Stock Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwoThousandThirteenIncentiveStockPlanMember_lbl" xml:lang="en-US">Two Thousand Thirteen Incentive Stock Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwoThousandThirteenIncentiveStockPlanMember_lbl" xml:lang="en-US">2013 Incentive Stock Plan [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xml:lang="en-US">Stock compensation vesting period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xml:lang="en-US">Exercisable time period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US">Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US">Weighted average remaining contractual life</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharePrice" xlink:label="us-gaap_SharePrice" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharePrice" xlink:to="us-gaap_SharePrice_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharePrice_lbl" xml:lang="en-US">Share price</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:to="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US">Options exercised</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StockOptionPlanExpense" xlink:label="us-gaap_StockOptionPlanExpense" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockOptionPlanExpense" xlink:to="us-gaap_StockOptionPlanExpense_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockOptionPlanExpense_lbl" xml:lang="en-US">Stock or Unit Option Plan Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockOptionPlanExpense_lbl" xml:lang="en-US">Stock options expense</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Threshold Share Price Trigger</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Threshold Share Price Trigger</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdSharePriceTrigger_lbl" xml:lang="en-US">Common stock trade share price</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Vesting Installment Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Vesting Installment Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardVestingInstallmentTerm_lbl" xml:lang="en-US">Annual installments</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Threshold Trading Days</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Threshold Trading Days</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdTradingDays_lbl" xml:lang="en-US">Common stock trading days</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Shares To Be Vested and Expected to Vest, Exercisable, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Shares To Be Vested and Expected to Vest, Exercisable, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsSharesToBeVestedAndExpectedToVestExercisableNumber_lbl" xml:lang="en-US">Shares to be vested and exercisable</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncomeAllocationEquivalentPercent" xlink:label="cli_IncomeAllocationEquivalentPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncomeAllocationEquivalentPercent" xlink:to="cli_IncomeAllocationEquivalentPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_IncomeAllocationEquivalentPercent_lbl" xml:lang="en-US">Income Allocation Equivalent, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncomeAllocationEquivalentPercent_lbl" xml:lang="en-US">Income Allocation Equivalent, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_IncomeAllocationEquivalentPercent_lbl" xml:lang="en-US">Income allocation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationDate_lbl" xml:lang="en-US">Common stock expiration date</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CashDistributionPercent" xlink:label="cli_CashDistributionPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CashDistributionPercent" xlink:to="cli_CashDistributionPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CashDistributionPercent_lbl" xml:lang="en-US">Cash Distribution, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CashDistributionPercent_lbl" xml:lang="en-US">Cash Distribution, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CashDistributionPercent_lbl" xml:lang="en-US">Percent of cash distribution</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Share price - weighted average fair value of options granted</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xml:lang="en-US">Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_lbl" xml:lang="en-US">Total unrecognized compensation cost</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xml:lang="en-US">Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xml:lang="en-US">Total unrecognized compensation cost, period of recognition</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AwardTypeAxis_lbl" xml:lang="en-US">Award Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US">Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US">Award Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="us-gaap_RestrictedStockMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedStockMember" xlink:to="us-gaap_RestrictedStockMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RestrictedStockMember_lbl" xml:lang="en-US">Restricted Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RestrictedStockMember_lbl" xml:lang="en-US">Restricted Stock [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TotalStockholderReturnBasedAwardsMember" xlink:label="cli_TotalStockholderReturnBasedAwardsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TotalStockholderReturnBasedAwardsMember" xlink:to="cli_TotalStockholderReturnBasedAwardsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TotalStockholderReturnBasedAwardsMember_lbl" xml:lang="en-US">Total Stockholder Return Based Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TotalStockholderReturnBasedAwardsMember_lbl" xml:lang="en-US">Total Stockholder Return Based Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TotalStockholderReturnBasedAwardsMember_lbl" xml:lang="en-US">Total Stockholder Return Based Awards [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Unvested In Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Unvested In Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsUnvestedInPeriod_lbl" xml:lang="en-US">Unvested performance shares</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US">Shares, Outstanding, Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US">Shares, Outstanding, Beginning balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US">Unvested stock outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/netLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US">Shares, Granted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US">Shares granted</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentageOfSharesVested" xlink:label="cli_PercentageOfSharesVested" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentageOfSharesVested" xlink:to="cli_PercentageOfSharesVested_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentageOfSharesVested_lbl" xml:lang="en-US">Percentage Of Shares Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentageOfSharesVested_lbl" xml:lang="en-US">Percentage Of Shares Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentageOfSharesVested_lbl" xml:lang="en-US">Percentage of shares vested</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod" xlink:to="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Performance Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_lbl" xml:lang="en-US">Share Based Compensation Arrangement By Share-based Payment Award Performance Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ShareBasedCompensationArrangementByShareBasedPaymentAwardPerformancePeriod_lbl" xml:lang="en-US">Performance period</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_PercentageOfAward" xlink:label="cli_PercentageOfAward" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PercentageOfAward" xlink:to="cli_PercentageOfAward_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PercentageOfAward_lbl" xml:lang="en-US">Percentage Of Award</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PercentageOfAward_lbl" xml:lang="en-US">Percentage Of Award</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_PercentageOfAward_lbl" xml:lang="en-US">Percent of the award</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RemainingPercentageOfAward" xlink:label="cli_RemainingPercentageOfAward" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RemainingPercentageOfAward" xlink:to="cli_RemainingPercentageOfAward_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RemainingPercentageOfAward_lbl" xml:lang="en-US">Remaining Percentage Of The Award</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RemainingPercentageOfAward_lbl" xml:lang="en-US">Remaining Percentage Of The Award</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RemainingPercentageOfAward_lbl" xml:lang="en-US">Remaining percent of the award</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_TotalStockholderReturnPercent" xlink:label="cli_TotalStockholderReturnPercent" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TotalStockholderReturnPercent" xlink:to="cli_TotalStockholderReturnPercent_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TotalStockholderReturnPercent_lbl" xml:lang="en-US">Total Stockholder Return, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TotalStockholderReturnPercent_lbl" xml:lang="en-US">Total Stockholder Return, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TotalStockholderReturnPercent_lbl" xml:lang="en-US">TSR percent</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit" xlink:to="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit_lbl" xml:lang="en-US">Common Stock Dividends Per Share Paid Percent, Payable On Common Unit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit_lbl" xml:lang="en-US">Common Stock Dividends Per Share Paid Percent, Payable On Common Unit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableOnCommonUnit_lbl" xml:lang="en-US">Dividends paid, percent representing common unit of limited partnership interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit" xlink:to="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit_lbl" xml:lang="en-US">Common Stock Dividends Per Share Paid Percent, Payable Upon Vesting Of Long-Term Investment Plan Unit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit_lbl" xml:lang="en-US">Common Stock Dividends Per Share Paid Percent, Payable Upon Vesting Of Long-Term Investment Plan Unit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonStockDividendsPerSharePaidPercentPayableUponVestingOfLongTermInvestmentPlanUnit_lbl" xml:lang="en-US">Dividends paid, percent payable upon vesting of LTIP Unit</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits" xlink:label="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits" xlink:to="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits_lbl" xml:lang="en-US">Maximum Percentage Of Retainer Fee Directors May Elect To Defer To Stock Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits_lbl" xml:lang="en-US">Maximum Percentage Of Retainer Fee Directors May Elect To Defer To Stock Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MaximumPercentageOfRetainerFeeDirectorsMayElectToDeferToStockUnits_lbl" xml:lang="en-US">Maximum percentage of retainer fee that directors may defer</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredStockUnitsSharesEarned" xlink:label="cli_DeferredStockUnitsSharesEarned" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredStockUnitsSharesEarned" xlink:to="cli_DeferredStockUnitsSharesEarned_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredStockUnitsSharesEarned_lbl" xml:lang="en-US">Deferred stock units earned.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredStockUnitsSharesEarned_lbl" xml:lang="en-US">Deferred Stock Units Shares Earned</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DeferredStockUnitsSharesEarned_lbl" xml:lang="en-US">Deferred stock units earned</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredStockUnitsOutstanding" xlink:label="cli_DeferredStockUnitsOutstanding" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredStockUnitsOutstanding" xlink:to="cli_DeferredStockUnitsOutstanding_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredStockUnitsOutstanding_lbl" xml:lang="en-US">Deferred stock units outstanding.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredStockUnitsOutstanding_lbl" xml:lang="en-US">Deferred Stock Units Outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_DeferredStockUnitsOutstanding_lbl" xml:lang="en-US">Deferred stock units outstanding</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnvestedRestrictedStockMember" xlink:label="cli_UnvestedRestrictedStockMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnvestedRestrictedStockMember" xlink:to="cli_UnvestedRestrictedStockMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnvestedRestrictedStockMember_lbl" xml:lang="en-US">Unvested Restricted Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnvestedRestrictedStockMember_lbl" xml:lang="en-US">Unvested Restricted Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnvestedRestrictedStockMember_lbl" xml:lang="en-US">Unvested Restricted Stock [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnvestedLongTermIncentivePlanAwardsMember" xlink:label="cli_UnvestedLongTermIncentivePlanAwardsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnvestedLongTermIncentivePlanAwardsMember" xlink:to="cli_UnvestedLongTermIncentivePlanAwardsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnvestedLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested Long-Term Incentive Plan Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnvestedLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested Long Term Incentive Plan Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnvestedLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested LTIP Units [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_UnvestedAoLongTermIncentivePlanAwardsMember" xlink:label="cli_UnvestedAoLongTermIncentivePlanAwardsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_UnvestedAoLongTermIncentivePlanAwardsMember" xlink:to="cli_UnvestedAoLongTermIncentivePlanAwardsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_UnvestedAoLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested AO Long-Term Incentive Plan Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_UnvestedAoLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested Ao Long Term Incentive Plan Awards [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_UnvestedAoLongTermIncentivePlanAwardsMember_lbl" xml:lang="en-US">Unvested AO LTIP Units [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockDividendsPerShareDeclared" xlink:to="us-gaap_CommonStockDividendsPerShareDeclared_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xml:lang="en-US">Dividends declared per common share</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest" xlink:label="us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest" xlink:to="us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest_lbl" xml:lang="en-US">Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_NetIncomeLossAttributableToNonredeemableNoncontrollingInterest_lbl" xml:lang="en-US">Net income</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable" xlink:to="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable_lbl" xml:lang="en-US">Noncontrolling Interest, Redemption Value Adjustment, Redeemable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable_lbl" xml:lang="en-US">Noncontrolling Interest, Redemption Value Adjustment, Redeemable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable_lbl" xml:lang="en-US">Add (deduct): Redeemable noncontrolling interests</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemable_lbl" xml:lang="en-US">Redeemable noncontrolling interests</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MinorityInterestDecreaseFromNoncontrollingInterest" xlink:label="cli_MinorityInterestDecreaseFromNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MinorityInterestDecreaseFromNoncontrollingInterest" xlink:to="cli_MinorityInterestDecreaseFromNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MinorityInterestDecreaseFromNoncontrollingInterest_lbl" xml:lang="en-US">Minority Interest, Decrease From Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MinorityInterestDecreaseFromNoncontrollingInterest_lbl" xml:lang="en-US">Minority Interest, Decrease From Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_MinorityInterestDecreaseFromNoncontrollingInterest_lbl" xml:lang="en-US">Change in noncontrolling interests in consolidated joint ventures</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StockBasedCompensationAttributableToNoncontrollingInterest" xlink:label="cli_StockBasedCompensationAttributableToNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_StockBasedCompensationAttributableToNoncontrollingInterest" xlink:to="cli_StockBasedCompensationAttributableToNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StockBasedCompensationAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Stock Based Compensation Attributable To Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StockBasedCompensationAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Stock Based Compensation Attributable To Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_StockBasedCompensationAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Stock compensation</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited" xlink:label="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited" xlink:to="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited_lbl" xml:lang="en-US">Stock Issued During Period, Value, Restricted Shares, Forfeited</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited_lbl" xml:lang="en-US">Stock Issued During Period, Value, Restricted Shares, Forfeited</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_StockIssuedDuringPeriodValueRestrictedSharesForfeited_lbl" xml:lang="en-US">Cancellation of unvested LTIP units</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:label="us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable" xlink:to="us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_lbl" xml:lang="en-US">Share-based Payment Arrangement, Option, Exercise Price Range [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_lbl" xml:lang="en-US">Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_lbl" xml:lang="en-US">Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_lbl" xml:lang="en-US">Shares Under Options - Outstanding, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions_lbl" xml:lang="en-US">Shares Under Options - Outstanding, beginning balance</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod" xlink:to="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod_lbl" xml:lang="en-US">ShareBased Compensation Arrangement By ShareBased Payment Award Options Grants, Forfeited, Or Expired In Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod_lbl" xml:lang="en-US">ShareBased Compensation Arrangement By ShareBased Payment Award Options Grants, Forfeited, Or Expired In Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriod_lbl" xml:lang="en-US">Shares Under Options - Granted, Lapsed or Cancelled</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions" xlink:to="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_lbl" xml:lang="en-US">Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfExercisableOptions_lbl" xml:lang="en-US">Shares Under Options - Options exercisable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xml:lang="en-US">Shares Under Options - Available for grant</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1" xlink:to="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" xml:lang="en-US">Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" xml:lang="en-US">Weighted Average Exercise Price - Outstanding, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_SharebasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeExercisableOptionsWeightedAverageExercisePrice1_lbl" xml:lang="en-US">Weighted Average Exercise Price - Outstanding, beginning balance</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriodWeightedAverageExercisePrice" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriodWeightedAverageExercisePrice" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US">ShareBased Compensation Arrangement By ShareBased Payment Award Options Grants, Forfeited, Or Expired In Period Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US">ShareBased Compensation Arrangement By ShareBased Payment Award Options Grants, Forfeited, Or Expired In Period Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsGrantsForfeitedOrExpiredInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US">Weighted Average Exercise Price - Granted, Lapsed or Cancelled</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xml:lang="en-US">Aggregate Intrinsic Value, Outstanding, ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_lbl" xml:lang="en-US">Aggregate Intrinsic Value, Outstanding, beginning balance</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCompensationArrangementWithIndividualExercisePrice" xlink:to="us-gaap_DeferredCompensationArrangementWithIndividualExercisePrice_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualExercisePrice_lbl" xml:lang="en-US">Deferred Compensation Arrangement with Individual, Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredCompensationArrangementWithIndividualExercisePrice_lbl" xml:lang="en-US">Outstanding stock option price</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:to="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_lbl" xml:lang="en-US">Expected life (in years)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_lbl" xml:lang="en-US">Risk-free interest rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_lbl" xml:lang="en-US">Volatility</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_lbl" xml:lang="en-US">Dividend yield</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xml:lang="en-US">Shares, Vested</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_lbl" xml:lang="en-US">Shares, Cancelled</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Weighted-Average Grant-Date Fair Value, Outstanding ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Weighted-Average Grant-Date Fair Value, Outstanding beginning balance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Weighted-Average Grant-Date Fair Value, Vested</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US">Weighted-Average Grant-Date Fair Value, Cancelled</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest" xlink:to="us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Income from continuing operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest_lbl" xml:lang="en-US">Net income</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership" xlink:to="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership_lbl" xml:lang="en-US">Noncontrolling Interest, Redemption Value Adjustment, Redeemable Before Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership_lbl" xml:lang="en-US">Noncontrolling Interest, Redemption Value Adjustment, Redeemable Before Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableBeforeOperatingPartnership_lbl" xml:lang="en-US">Add (deduct): Redemption value adjustment of redeemable noncontrolling interests attributable to common shareholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US">Net income available to common shareholders for basic earnings per share</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership" xlink:to="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership_lbl" xml:lang="en-US">Noncontrolling Interest Redemption Value Adjustment Redeemable In Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership_lbl" xml:lang="en-US">Noncontrolling Interest Redemption Value Adjustment Redeemable In Operating Partnership</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_NoncontrollingInterestRedemptionValueAdjustmentRedeemableInOperatingPartnership_lbl" xml:lang="en-US">Add (deduct): Redemption value adjustment of redeemable noncontrolling interests in Operating Partnership unitholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xml:lang="en-US">Net income available for diluted earnings per share</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnits" xlink:label="cli_CommonUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnits" xlink:to="cli_CommonUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnits_lbl" xml:lang="en-US">Common units.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnits_lbl" xml:lang="en-US">Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_CommonUnits_lbl" xml:lang="en-US">Add: Operating Partnership - common and vested LTIP units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RestrictedStockAwardsShares" xlink:label="cli_RestrictedStockAwardsShares" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RestrictedStockAwardsShares" xlink:to="cli_RestrictedStockAwardsShares_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RestrictedStockAwardsShares_lbl" xml:lang="en-US">Restricted Stock Awards, shares.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RestrictedStockAwardsShares_lbl" xml:lang="en-US">Restricted Stock Awards Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_RestrictedStockAwardsShares_lbl" xml:lang="en-US">Restricted Stock Awards</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_StockOptions" xlink:label="cli_StockOptions" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_StockOptions_lbl" xml:lang="en-US">Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_StockOptions_lbl" xml:lang="en-US">Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_StockOptions_lbl" xml:lang="en-US">Stock Options</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_FutureDevelopmentsMember" xlink:label="cli_FutureDevelopmentsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_FutureDevelopmentsMember" xlink:to="cli_FutureDevelopmentsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FutureDevelopmentsMember_lbl" xml:lang="en-US">Future Developments [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FutureDevelopmentsMember_lbl" xml:lang="en-US">Future Developments [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FutureDevelopmentsMember_lbl" xml:lang="en-US">Future Developments [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits" xlink:label="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits" xlink:to="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits_lbl" xml:lang="en-US">Number Of Common Shares Received Upon Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits_lbl" xml:lang="en-US">Number Of Common Shares Received Upon Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NumberOfCommonSharesReceivedUponRedemptionOfCommonUnits_lbl" xml:lang="en-US">Number of common shares received upon redemption of common units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RebalanceOfOwnershipPercentage" xlink:label="cli_RebalanceOfOwnershipPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RebalanceOfOwnershipPercentage" xlink:to="cli_RebalanceOfOwnershipPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RebalanceOfOwnershipPercentage_lbl" xml:lang="en-US">Rebalance Of Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RebalanceOfOwnershipPercentage_lbl" xml:lang="en-US">Rebalance Of Ownership Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_RebalanceOfOwnershipPercentage_lbl" xml:lang="en-US">Rebalance of ownership percentage</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners" xlink:to="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_lbl" xml:lang="en-US">Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_lbl" xml:lang="en-US">Percentage of noncontrolling interest</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DistributionOfCashFlowToIndividualCompaniesPercentage" xlink:label="cli_DistributionOfCashFlowToIndividualCompaniesPercentage" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DistributionOfCashFlowToIndividualCompaniesPercentage" xlink:to="cli_DistributionOfCashFlowToIndividualCompaniesPercentage_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DistributionOfCashFlowToIndividualCompaniesPercentage_lbl" xml:lang="en-US">Distribution of cash flow to individual companies percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DistributionOfCashFlowToIndividualCompaniesPercentage_lbl" xml:lang="en-US">Distribution Of Cash Flow To Individual Companies Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DistributionOfCashFlowToIndividualCompaniesPercentage_lbl" xml:lang="en-US">Excess net cash flow remaining after the distribution to the Company</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsRedeemedForCommonShares" xlink:label="cli_CommonUnitsRedeemedForCommonShares" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsRedeemedForCommonShares" xlink:to="cli_CommonUnitsRedeemedForCommonShares_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsRedeemedForCommonShares_lbl" xml:lang="en-US">Common Units Redeemed For Common Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsRedeemedForCommonShares_lbl" xml:lang="en-US">Common Units Redeemed For Common Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="cli_CommonUnitsRedeemedForCommonShares_lbl" xml:lang="en-US">Redemption of common units for shares of common stock</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsIssuanceOfUnits" xlink:label="cli_CommonUnitsIssuanceOfUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsIssuanceOfUnits" xlink:to="cli_CommonUnitsIssuanceOfUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsIssuanceOfUnits_lbl" xml:lang="en-US">Common Units, Issuance Of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsIssuanceOfUnits_lbl" xml:lang="en-US">Common Units, Issuance Of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitsIssuanceOfUnits_lbl" xml:lang="en-US">Issuance of units, Common Units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsRedemptionOfCommonUnits" xlink:label="cli_CommonUnitsRedemptionOfCommonUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsRedemptionOfCommonUnits" xlink:to="cli_CommonUnitsRedemptionOfCommonUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsRedemptionOfCommonUnits_lbl" xml:lang="en-US">Common Units, Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsRedemptionOfCommonUnits_lbl" xml:lang="en-US">Common Units, Redemption Of Common Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitsRedemptionOfCommonUnits_lbl" xml:lang="en-US">Redemption of common units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock" xlink:label="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock" xlink:to="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock_lbl" xml:lang="en-US">Common Units, Conversion Of Vested LTIP Units To Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock_lbl" xml:lang="en-US">Common Units, Conversion Of Vested LTIP Units To Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitsConversionOfVestedLtipUnitsToCommonStock_lbl" xml:lang="en-US">Conversion of vested LTIP units to common units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_CommonUnitsVestedLtipUnits" xlink:label="cli_CommonUnitsVestedLtipUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_CommonUnitsVestedLtipUnits" xlink:to="cli_CommonUnitsVestedLtipUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonUnitsVestedLtipUnits_lbl" xml:lang="en-US">Common Units, Vested LTIP Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonUnitsVestedLtipUnits_lbl" xml:lang="en-US">Common Units, Vested LTIP Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonUnitsVestedLtipUnits_lbl" xml:lang="en-US">Vested LTIP units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermIncentivePlanIssuanceOfUnits" xlink:label="cli_LongTermIncentivePlanIssuanceOfUnits" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermIncentivePlanIssuanceOfUnits" xlink:to="cli_LongTermIncentivePlanIssuanceOfUnits_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermIncentivePlanIssuanceOfUnits_lbl" xml:lang="en-US">Long Term Incentive Plan, Issuance of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermIncentivePlanIssuanceOfUnits_lbl" xml:lang="en-US">Long Term Incentive Plan, Issuance of Units</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LongTermIncentivePlanIssuanceOfUnits_lbl" xml:lang="en-US">Issuance of units, LTIP Units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermIncentivePlanVested" xlink:label="cli_LongTermIncentivePlanVested" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermIncentivePlanVested" xlink:to="cli_LongTermIncentivePlanVested_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermIncentivePlanVested_lbl" xml:lang="en-US">Long Term Incentive Plan, Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermIncentivePlanVested_lbl" xml:lang="en-US">Long Term Incentive Plan, Vested</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LongTermIncentivePlanVested_lbl" xml:lang="en-US">Vested LTIP units</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LongTermIncentivePlanUnitsForfeited" xlink:label="cli_LongTermIncentivePlanUnitsForfeited" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_LongTermIncentivePlanUnitsForfeited" xlink:to="cli_LongTermIncentivePlanUnitsForfeited_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LongTermIncentivePlanUnitsForfeited_lbl" xml:lang="en-US">Long Term Incentive Plan Units Forfeited</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LongTermIncentivePlanUnitsForfeited_lbl" xml:lang="en-US">Long Term Incentive Plan Units Forfeited</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="cli_LongTermIncentivePlanUnitsForfeited_lbl" xml:lang="en-US">Cancellation of units</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:to="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_lbl" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementGeographicalAxis" xlink:label="srt_StatementGeographicalAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementGeographicalAxis" xlink:to="srt_StatementGeographicalAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_StatementGeographicalAxis_lbl" xml:lang="en-US">Geographical [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_SegmentGeographicalDomain" xlink:label="srt_SegmentGeographicalDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SegmentGeographicalDomain" xlink:to="srt_SegmentGeographicalDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_SegmentGeographicalDomain_lbl" xml:lang="en-US">Segment Geographical [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_SegmentGeographicalDomain_lbl" xml:lang="en-US">Geographical [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_ForeignCountryMember" xlink:label="us-gaap_ForeignCountryMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForeignCountryMember" xlink:to="us-gaap_ForeignCountryMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ForeignCountryMember_lbl" xml:lang="en-US">Foreign Country [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ForeignCountryMember_lbl" xml:lang="en-US">Foreign Locations [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NumberOfReportableSegments" xlink:label="us-gaap_NumberOfReportableSegments" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NumberOfReportableSegments" xlink:to="us-gaap_NumberOfReportableSegments_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xml:lang="en-US">Number of Reportable Segments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NumberOfReportableSegments_lbl" xml:lang="en-US">Number of business segments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NoncurrentAssets" xlink:label="us-gaap_NoncurrentAssets" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoncurrentAssets" xlink:to="us-gaap_NoncurrentAssets_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoncurrentAssets_lbl" xml:lang="en-US">Long-Lived Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoncurrentAssets_lbl" xml:lang="en-US">Long lived assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="us-gaap_StatementBusinessSegmentsAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementBusinessSegmentsAxis" xlink:to="us-gaap_StatementBusinessSegmentsAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementBusinessSegmentsAxis_lbl" xml:lang="en-US">Business Segments [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_SegmentDomain" xlink:label="us-gaap_SegmentDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentDomain" xlink:to="us-gaap_SegmentDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SegmentDomain_lbl" xml:lang="en-US">Segment [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentDomain_lbl" xml:lang="en-US">Segment [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RealEstateCommercialAndOtherSegmentMember" xlink:label="cli_RealEstateCommercialAndOtherSegmentMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealEstateCommercialAndOtherSegmentMember" xlink:to="cli_RealEstateCommercialAndOtherSegmentMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealEstateCommercialAndOtherSegmentMember_lbl" xml:lang="en-US">Real Estate Commercial And Other Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealEstateCommercialAndOtherSegmentMember_lbl" xml:lang="en-US">Real Estate Commercial And Other Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RealEstateCommercialAndOtherSegmentMember_lbl" xml:lang="en-US">Commercial And Other Real Estate [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_MultipleFamilyRealEstateAndServicesSegmentMember" xlink:label="cli_MultipleFamilyRealEstateAndServicesSegmentMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_MultipleFamilyRealEstateAndServicesSegmentMember" xlink:to="cli_MultipleFamilyRealEstateAndServicesSegmentMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MultipleFamilyRealEstateAndServicesSegmentMember_lbl" xml:lang="en-US">Multiple-Family Real Estate And Services Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MultipleFamilyRealEstateAndServicesSegmentMember_lbl" xml:lang="en-US">Multiple Family Real Estate And Services Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MultipleFamilyRealEstateAndServicesSegmentMember_lbl" xml:lang="en-US">Multiple-Family Real Estate &amp; Services [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_OperatingAndInterestExpenses" xlink:label="cli_OperatingAndInterestExpenses" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OperatingAndInterestExpenses" xlink:to="cli_OperatingAndInterestExpenses_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_OperatingAndInterestExpenses_lbl" xml:lang="en-US">Total operating and interest expenses.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_OperatingAndInterestExpenses_lbl" xml:lang="en-US">Operating And Interest Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="cli_OperatingAndInterestExpenses_lbl" xml:lang="en-US">Total operating and interest expenses</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SegmentReportingInformationNetOperatingIncomeLossForReportableSegment" xlink:label="cli_SegmentReportingInformationNetOperatingIncomeLossForReportableSegment" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SegmentReportingInformationNetOperatingIncomeLossForReportableSegment" xlink:to="cli_SegmentReportingInformationNetOperatingIncomeLossForReportableSegment_lbl" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RealEstateServicesMember" xlink:to="cli_RealEstateServicesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RealEstateServicesMember_lbl" xml:lang="en-US">Real Estate Services [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RealEstateServicesMember_lbl" xml:lang="en-US">Real Estate Services [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RealEstateServicesMember_lbl" xml:lang="en-US">Real Estate Services [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ParkingMember_lbl" xml:lang="en-US">Parking Income [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_HotelMember_lbl" xml:lang="en-US">Hotel [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_HotelMember_lbl" xml:lang="en-US">Hotel Income [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOtherMember_lbl" xml:lang="en-US">Real Estate Other [Member]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PublicUtilitiesMember" xlink:label="us-gaap_PublicUtilitiesMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PublicUtilitiesMember" xlink:to="us-gaap_PublicUtilitiesMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PublicUtilitiesMember_lbl" xml:lang="en-US">Public Utilities [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralPartnerMember" xlink:to="us-gaap_GeneralPartnerMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GeneralPartnerMember_lbl" xml:lang="en-US">General Partner [Member]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_LimitedPartnerMember" xlink:label="us-gaap_LimitedPartnerMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LimitedPartnerMember_lbl" xml:lang="en-US">Limited Partner [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LimitedPartnerMember_lbl" xml:lang="en-US">Limited Partner Common Units/Vested LTIP Units [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_GeneralPartnerCommonUnitholdersMember" xlink:label="cli_GeneralPartnerCommonUnitholdersMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_GeneralPartnerCommonUnitholdersMember_lbl" xml:lang="en-US">General Partner Common Unitholders [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_GeneralPartnerCommonUnitholdersMember_lbl" xml:lang="en-US">General Partner Common Unitholders [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_GeneralPartnerCommonUnitholdersMember_lbl" xml:lang="en-US">General Partner Common Unitholders [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_LimitedPartnersCommonUnitholdersMember" xlink:label="cli_LimitedPartnersCommonUnitholdersMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_LimitedPartnersCommonUnitholdersMember_lbl" xml:lang="en-US">Limited Partners Common Unitholders [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_LimitedPartnersCommonUnitholdersMember_lbl" xml:lang="en-US">Limited Partners Common Unitholders [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_LimitedPartnersCommonUnitholdersMember_lbl" xml:lang="en-US">Limited Partner Common Unitholders [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_OtherOwnershipInterestMember" xlink:label="us-gaap_OtherOwnershipInterestMember" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" xlink:label="us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_lbl" xml:lang="en-US">Disposal Groups, Including Discontinued Operations, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember" xlink:label="us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_MarbellaTowerUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">Marbella Tower Urban Renewal Associates LLC [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MarbellaTowerUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">Marbella Tower Urban Renewal Associates Llc [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MarbellaTowerUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">Marbella Tower Urban Renewal Associates LLC [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_XsHotelUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">XS Hotel Urban Renewal Associates LLC [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_XsHotelUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">Xs Hotel Urban Renewal Associates Llc [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_XsHotelUrbanRenewalAssociatesLlcMember_lbl" xml:lang="en-US">XS Hotel Urban Renewal Associates LLC [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_NotesReceivableThreeMember_lbl" xml:lang="en-US">Notes Receivable Three [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReceivableTypeDomain" xlink:to="us-gaap_ReceivableTypeDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ReceivableTypeDomain_lbl" xml:lang="en-US">Receivable Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ReceivableTypeDomain_lbl" xml:lang="en-US">Receivable [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InterestFreeNotesReceivableMember" xlink:label="cli_InterestFreeNotesReceivableMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InterestFreeNotesReceivableMember_lbl" xml:lang="en-US">Interest Free Notes Receivable [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InterestFreeNotesReceivableMember_lbl" xml:lang="en-US">Interest Free Notes Receivable [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InterestFreeNotesReceivableMember_lbl" xml:lang="en-US">Interest-Free Notes Receivable [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonrecurringAdjustmentAxis" xlink:label="us-gaap_NonrecurringAdjustmentAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonrecurringAdjustmentAxis" xlink:to="us-gaap_NonrecurringAdjustmentAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NonrecurringAdjustmentAxis_lbl" xml:lang="en-US">Nonrecurring Adjustment [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_NonrecurringAdjustmentDomain" xlink:label="us-gaap_NonrecurringAdjustmentDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NonrecurringAdjustmentDomain" xlink:to="us-gaap_NonrecurringAdjustmentDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NonrecurringAdjustmentDomain_lbl" xml:lang="en-US">Nonrecurring Adjustment [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NonrecurringAdjustmentDomain_lbl" xml:lang="en-US">Nonrecurring Adjustment [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_AcquisitionRelatedCostsMember" xlink:label="us-gaap_AcquisitionRelatedCostsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AcquisitionRelatedCostsMember" xlink:to="us-gaap_AcquisitionRelatedCostsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AcquisitionRelatedCostsMember_lbl" xml:lang="en-US">Acquisition Related Costs [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AcquisitionRelatedCostsMember_lbl" xml:lang="en-US">Acquisition-related Costs [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="us-gaap_InterestRateSwapMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestRateSwapMember_lbl" xml:lang="en-US">Interest Rate Swap [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestRateSwapMember_lbl" xml:lang="en-US">Interest Rate Swaps [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationAxis" xlink:label="us-gaap_BalanceSheetLocationAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationAxis" xlink:to="us-gaap_BalanceSheetLocationAxis_lbl" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_BalanceSheetLocationDomain" xlink:label="us-gaap_BalanceSheetLocationDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BalanceSheetLocationDomain" xlink:to="us-gaap_BalanceSheetLocationDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xml:lang="en-US">Balance Sheet Location [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BalanceSheetLocationDomain_lbl" xml:lang="en-US">Balance Sheet Location [Domain]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_DeferredChargesGoodwillAndOtherAssetsMember" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_DeferredChargesGoodwillAndOtherAssetsMember" xlink:to="cli_DeferredChargesGoodwillAndOtherAssetsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsMember_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsMember_lbl" xml:lang="en-US">Deferred Charges Goodwill And Other Assets [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_DeferredChargesGoodwillAndOtherAssetsMember_lbl" xml:lang="en-US">Deferred Charges, Goodwill And Other Assets [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="us-gaap_IncomeStatementLocationAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xml:lang="en-US">Income Statement Location [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="us-gaap_IncomeStatementLocationDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_IncomeStatementLocationDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xml:lang="en-US">Income Statement Location [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xml:lang="en-US">Income Statement Location [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_InterestExpenseMember" xlink:label="us-gaap_InterestExpenseMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpenseMember" xlink:to="us-gaap_InterestExpenseMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpenseMember_lbl" xml:lang="en-US">Interest Expense [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpenseMember_lbl" xml:lang="en-US">Interest Expense [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_InterestAndOtherInvestmentIncomeLossMember" xlink:label="cli_InterestAndOtherInvestmentIncomeLossMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InterestAndOtherInvestmentIncomeLossMember" xlink:to="cli_InterestAndOtherInvestmentIncomeLossMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InterestAndOtherInvestmentIncomeLossMember_lbl" xml:lang="en-US">Interest And Other Investment Income (Loss) [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InterestAndOtherInvestmentIncomeLossMember_lbl" xml:lang="en-US">Interest And Other Investment Income Loss [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InterestAndOtherInvestmentIncomeLossMember_lbl" xml:lang="en-US">Interest And Other Investment Income (Loss) [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember" xlink:label="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember" xlink:to="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember_lbl" xml:lang="en-US">Four Point Five Zero Zero Percent Senior Unsecured Notes Due April Eighteen Two Thousand Twenty Two [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember_lbl" xml:lang="en-US">Four Point Five Zero Zero Percent Senior Unsecured Notes Due April Eighteen Two Thousand Twenty Two [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FourPointFiveZeroZeroPercentSeniorUnsecuredNotesDueAprilEighteenTwoThousandTwentyTwoMember_lbl" xml:lang="en-US">4.500% Senior Unsecured Notes Due April 18, 2022 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember" xlink:label="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember" xlink:to="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember_lbl" xml:lang="en-US">3.150% Senior Unsecured Note, Due May 15, 2023 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember_lbl" xml:lang="en-US">Three Point One Five Zero Percent Senior Unsecured Notes Due May Fifteenth Two Thousand Twenty Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_ThreePointOneFiveZeroPercentSeniorUnsecuredNotesDueMayFifteenthTwoThousandTwentyThreeMember_lbl" xml:lang="en-US">3.150% Senior Unsecured Notes, Due May 15, 2023 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember" xlink:label="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember" xlink:to="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember_lbl" xml:lang="en-US">5.800% Senior Unsecured Notes, due January 15, 2016</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember_lbl" xml:lang="en-US">Five Point Eight Zero Zero Percent Senior Unsecured Notes Due January Fifteen Two Thousand Sixteen [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FivePointEightZeroZeroPercentSeniorUnsecuredNotesDueJanuaryFifteenTwoThousandSixteenMember_lbl" xml:lang="en-US">5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_IncrementalCommitmentsMember" xlink:label="cli_IncrementalCommitmentsMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_IncrementalCommitmentsMember" xlink:to="cli_IncrementalCommitmentsMember_lbl" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_IncrementalCommitmentsMember_lbl" xml:lang="en-US">Incremental Commitments [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FortyFiveUnsecuredTermLoanPercentLeverageRatioMember_lbl" xml:lang="en-US">Forty Five Unsecured Term Loan Percent Leverage Ratio [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FortyFiveAndFiftyUnsecuredTermLoanPercentLeverageRatioMember_lbl" xml:lang="en-US">45% And 50% Unsecured Term Loan Leverage Ratio [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FiftyAndFiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">Fifty And Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FiftyAndFiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">Fifty And Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FiftyAndFiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">50% And 55% Unsecured Term Loan Leverage Ratio [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_FiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_FiftyFivePercentUnsecuredTermLoanLeverageRatioMember_lbl" xml:lang="en-US">55% Unsecured Term Loan Leverage Ratio [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_CreditRatingMoodysAxis_lbl" xml:lang="en-US">Credit Rating, Moody's [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ExternalCreditRatingMoodysMember_lbl" xml:lang="en-US">External Credit Rating, Moody's [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoRatingsOrLessThanMoodysBaa3RatingMember_lbl" xml:lang="en-US">No Ratings Or Less Than Moodys Baa3 Rating [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NoRatingsOrLessThanMoodysBaa3RatingMember_lbl" xml:lang="en-US">No Ratings Or Less Than Baa3 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MoodysBaa3RatingMember_lbl" xml:lang="en-US">Baa3 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MoodysBaa2RatingMember_lbl" xml:lang="en-US">Baa2 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MoodysBaa1RatingMember_lbl" xml:lang="en-US">Baa1 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MoodysA3RatingOrHigherMember_lbl" xml:lang="en-US">Moodys A3 Rating Or Higher [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ExternalCreditRatingStandardPoorsMember_lbl" xml:lang="en-US">External Credit Rating, Standard &amp; Poor's [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_NoRatingsOrLessThanStandardPoorsBBBMinusMember_lbl" xml:lang="en-US">No Ratings Or Less Than Standard Poors B B B Minus [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_NoRatingsOrLessThanStandardPoorsBBBMinusMember_lbl" xml:lang="en-US">No Ratings Or Less Than BBB- [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_StandardPoorsBBBMinusRatingMember_lbl" xml:lang="en-US">BBB- [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_StandardPoorsBBBRatingMember_lbl" xml:lang="en-US">BBB [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_StandardPoorsBBBPlusRatingMember_lbl" xml:lang="en-US">BBB+ [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_FiftyFivePercentUnsecured2016TermLoanLeverageRatioMember_lbl" xml:lang="en-US">Fifty Five Percent Unsecured2016 Term Loan Leverage Ratio [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_WorcesterMember_lbl" xml:lang="en-US">Worcester [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_MonacoTowersMember_lbl" xml:lang="en-US">Monaco Towers [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_MonacoTowersMember_lbl" xml:lang="en-US">Monaco [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_PortImperialHotelDevelopmentMember_lbl" xml:lang="en-US">Port Imperial Hotel Development [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_PortImperialHotelDevelopmentMember_lbl" xml:lang="en-US">Port Imperial Hotel Development [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_OneOneOneRiverRealtyMember" xlink:to="cli_OneOneOneRiverRealtyMember_lbl" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_PortImperialSouthParcel89Member" xlink:to="cli_PortImperialSouthParcel89Member_lbl" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxPeriodDomain_lbl" xml:lang="en-US">Tax Period [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TaxYearOneMember_lbl" xml:lang="en-US">Tax Year One [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TaxYearOneMember_lbl" xml:lang="en-US">Tax Year 1 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TaxYearTwoMember_lbl" xml:lang="en-US">Tax Year Two [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TaxYearTwoMember_lbl" xml:lang="en-US">Tax Year Two [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TaxYearTwoMember_lbl" xml:lang="en-US">Tax Year 2 [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TaxYearThreeMember" xlink:to="cli_TaxYearThreeMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TaxYearThreeMember_lbl" xml:lang="en-US">Tax Year Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TaxYearThreeMember_lbl" xml:lang="en-US">Tax Year Three [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TaxYearThreeMember_lbl" xml:lang="en-US">Tax Year 3 [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TaxYearFourMember" xlink:to="cli_TaxYearFourMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TaxYearFourMember_lbl" xml:lang="en-US">Tax Year Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TaxYearFourMember_lbl" xml:lang="en-US">Tax Year Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TaxYearFourMember_lbl" xml:lang="en-US">Tax Year 4 [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_TaxYearFiveMember" xlink:to="cli_TaxYearFiveMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TaxYearFiveMember_lbl" xml:lang="en-US">Tax Year Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TaxYearFiveMember_lbl" xml:lang="en-US">Tax Year Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TaxYearFiveMember_lbl" xml:lang="en-US">Tax Year 5 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_YearsOneToFourMember" xlink:label="cli_YearsOneToFourMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_YearsOneToFourMember" xlink:to="cli_YearsOneToFourMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsOneToFourMember_lbl" xml:lang="en-US">Years One To Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsOneToFourMember_lbl" xml:lang="en-US">Years One To Four [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsOneToFourMember_lbl" xml:lang="en-US">Years 1-4 [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_YearsFiveToEightMember" xlink:to="cli_YearsFiveToEightMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsFiveToEightMember_lbl" xml:lang="en-US">Years Five To Eight [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsFiveToEightMember_lbl" xml:lang="en-US">Years Five To Eight [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsFiveToEightMember_lbl" xml:lang="en-US">Years 5-8 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_YearsNineToTenMember" xlink:label="cli_YearsNineToTenMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_YearsNineToTenMember" xlink:to="cli_YearsNineToTenMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsNineToTenMember_lbl" xml:lang="en-US">Years Nine To Ten [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsNineToTenMember_lbl" xml:lang="en-US">Years Nine To Ten [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsNineToTenMember_lbl" xml:lang="en-US">Years 9-10 [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_YearsOneToTenMember" xlink:label="cli_YearsOneToTenMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_YearsOneToTenMember" xlink:to="cli_YearsOneToTenMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsOneToTenMember_lbl" xml:lang="en-US">Years One To Ten [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsOneToTenMember_lbl" xml:lang="en-US">Years One To Ten [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsOneToTenMember_lbl" xml:lang="en-US">Years 1-10 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsElevenToEighteenMember_lbl" xml:lang="en-US">Years Eleven To Eighteen [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsElevenToEighteenMember_lbl" xml:lang="en-US">Years Eleven To Eighteen [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsElevenToEighteenMember_lbl" xml:lang="en-US">Years 11-18 [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_YearsNineteenToTwentyFiveMember_lbl" xml:lang="en-US">Years Nineteen To Twenty-Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_YearsNineteenToTwentyFiveMember_lbl" xml:lang="en-US">Years Nineteen To Twenty Five [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_YearsNineteenToTwentyFiveMember_lbl" xml:lang="en-US">Years 19-25 [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_StatementScenarioAxis" xlink:label="srt_StatementScenarioAxis" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_StatementScenarioAxis" xlink:to="srt_StatementScenarioAxis_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_StatementScenarioAxis_lbl" xml:lang="en-US">Scenario [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="srt_ScenarioUnspecifiedDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScenarioUnspecifiedDomain" xlink:to="srt_ScenarioUnspecifiedDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US">Scenario Unspecified [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US">Scenario, Unspecified [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2019/elts/srt-2019-01-31.xsd#srt_ScenarioForecastMember" xlink:label="srt_ScenarioForecastMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ScenarioForecastMember" xlink:to="srt_ScenarioForecastMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ScenarioForecastMember_lbl" xml:lang="en-US">Scenario Forecast [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ScenarioForecastMember_lbl" xml:lang="en-US">Scenario, Forecast [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_XsPortImperialHotelLlcMember" xlink:label="cli_XsPortImperialHotelLlcMember" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_XsPortImperialHotelLlcMember" xlink:to="cli_XsPortImperialHotelLlcMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_XsPortImperialHotelLlcMember_lbl" xml:lang="en-US">XS Port Imperial Hotel, LLC [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_XsPortImperialHotelLlcMember_lbl" xml:lang="en-US">Xs Port Imperial Hotel Llc [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_XsPortImperialHotelLlcMember_lbl" xml:lang="en-US">XS Port Imperial Hotel, LLC [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_ChaseIiiOverlookRidgeMember" xlink:label="cli_ChaseIiiOverlookRidgeMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VestingAxis_lbl" xml:lang="en-US">Vesting [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VestingDomain_lbl" xml:lang="en-US">Vesting [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_VestingDomain_lbl" xml:lang="en-US">Vesting [Domain]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ThreeEqualAnnualInstallmentMember_lbl" xml:lang="en-US">Three Equal Annual Installment [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_CommonStockTradesMember_lbl" xml:lang="en-US">Common Stock Trades [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_CommonStockTradesMember_lbl" xml:lang="en-US">Common Stock Trades [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_CommonStockTradesMember_lbl" xml:lang="en-US">Common Stock Trades [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_ParticipationRightsMember_lbl" xml:lang="en-US">Participation Rights [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RoselandResidentialL.p.Member_lbl" xml:lang="en-US">Roseland Residential, L.P. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RoselandResidentialL.p.Member_lbl" xml:lang="en-US">Roseland Residential L.p. [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RelatedPartyTransactionAxis_lbl" xml:lang="en-US">Related Party Transaction [Axis]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RelatedPartyTransactionDomain_lbl" xml:lang="en-US">Related Party Transaction [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RelatedPartyTransactionDomain_lbl" xml:lang="en-US">Related Party Transaction [Domain]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_InvestmentAgreementMember" xlink:to="cli_InvestmentAgreementMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_InvestmentAgreementMember_lbl" xml:lang="en-US">Investment Agreement [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_InvestmentAgreementMember_lbl" xml:lang="en-US">Investment Agreement [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_InvestmentAgreementMember_lbl" xml:lang="en-US">Investment Agreement [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredUnitsByNameAxis" xlink:label="us-gaap_PreferredUnitsByNameAxis" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2019/elts/us-gaap-2019-01-31.xsd#us-gaap_PreferredUnitsClassDomain" xlink:label="us-gaap_PreferredUnitsClassDomain" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PreferredUnitsClassDomain" xlink:to="us-gaap_PreferredUnitsClassDomain_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredUnitsClassDomain_lbl" xml:lang="en-US">Preferred Units Class [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredUnitsClassDomain_lbl" xml:lang="en-US">Preferred Units, Class [Domain]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_SeriesUnitsMember" xlink:to="cli_SeriesUnitsMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_SeriesUnitsMember_lbl" xml:lang="en-US">Series A Units [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SeriesUnitsMember_lbl" xml:lang="en-US">Series Units [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SeriesUnitsMember_lbl" xml:lang="en-US">Series A Units [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_SeriesOnePreferredLimitedPartnershipUnitsMember" xlink:label="cli_SeriesOnePreferredLimitedPartnershipUnitsMember" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_SeriesOnePreferredLimitedPartnershipUnitsMember_lbl" xml:lang="en-US">Series One Preferred Limited Partnership Units [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_SeriesOnePreferredLimitedPartnershipUnitsMember_lbl" xml:lang="en-US">Series A-1 Units [Member]</label>
    <loc xlink:type="locator" xlink:href="cli-20190331.xsd#cli_RockpointGroupL.l.c.Member" xlink:label="cli_RockpointGroupL.l.c.Member" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RockpointGroupL.l.c.Member_lbl" xml:lang="en-US">Rockpoint Group, L.L.C. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RockpointGroupL.l.c.Member_lbl" xml:lang="en-US">Rockpoint Group L.l.c. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RockpointGroupL.l.c.Member_lbl" xml:lang="en-US">Rockpoint [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="cli_RoselandResidentialTrustMember" xlink:to="cli_RoselandResidentialTrustMember_lbl" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RoselandResidentialTrustMember_lbl" xml:lang="en-US">Roseland Residential Trust [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RoselandResidentialTrustMember_lbl" xml:lang="en-US">Roseland Residential Trust [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_RoselandResidentialTrustMember_lbl" xml:lang="en-US">RRT [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_RedeemableNoncontrollingInterestsMember_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_RedeemableNoncontrollingInterestsMember_lbl" xml:lang="en-US">Redeemable Noncontrolling Interests [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwoThousandSixteenTimeBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">2016 TBV LTIP Units [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwoThousandSeventeenLongTermIncentivePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Long Term Incentive Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwoThousandSeventeenLongTermIncentivePlanMember_lbl" xml:lang="en-US">2017 LTIP Awards [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TwoThousandSeventeenOutperformancePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Outperformance Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwoThousandSeventeenOutperformancePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Outperformance Plan [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwoThousandSeventeenPerformanceBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Performance Based Vesting Long Term Incentive Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwoThousandSeventeenPerformanceBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">2017 PBV LTIP Units [Member]</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="cli_TwoThousandSeventeenTimeBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Time-Based Vesting Long-Term Incentive Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="cli_TwoThousandSeventeenTimeBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">Two Thousand Seventeen Time Based Vesting Long Term Incentive Plan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="cli_TwoThousandSeventeenTimeBasedVestingLongTermIncentivePlanMember_lbl" xml:lang="en-US">2017 TBV LTIP Units [Member]</label>
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