Exhibit
10.1


FOURTH
MODIFICATION AGREEMENT


This FOURTH MODIFICATION AGREEMENT (this “Agreement”)
is made as of September 21, 2007 by and among (a) Mack-Cali Realty, L.P. (the “Borrower”), (b) the Lenders party
hereto, and (c) JPMorgan Chase Bank, N.A. as Administrative Agent (in such
capacity, the “Administrative Agent”) for
the Lenders.


WHEREAS, the Borrower, the Lenders and the Administrative Agent are
parties to a Second Amended and Restated Revolving Credit Agreement dated as of
November 23, 2004, as modified by the Extension and Modification Agreement
dated as of September 16, 2005, the Second Modification Agreement dated as of
July 14, 2006, and the Extension and Third Modification Agreement dated as of
June 22, 2007 (as so modified, the “Credit Agreement”),
pursuant to which the Lenders have agreed to make loans to the Borrower on the
terms and conditions set forth therein; and


WHEREAS, the Borrower has elected to exercise its option to increase
the Total Commitment under the Credit Agreement, and the Lenders party hereto
are willing to increase their respective Commitments under the Credit Agreement
on the terms and conditions set forth herein;


NOW, THEREFORE, in consideration of the foregoing premises, and for
other good and valuable consideration, the receipt and sufficiency of which are
hereby acknowledged, and fully intending to be legally bound by this Agreement,
the parties hereto agree as follows:


1.             Definitions.  Capitalized terms used herein without
definition shall have the meanings assigned to such terms in the Credit
Agreement.


2.             Modifications
to Credit Agreement.  As of the
Effective Date (as defined in §4 hereof) the Credit Agreement is modified as
follows:


2.1.         Modifications
to §1.1.  The definition of the
term “Total Commitment” set forth in §1.1 of the Credit Agreement is hereby
modified by restating such definition in its entirety to read as follows:


“Total Commitment.  As of any date, the sum of the then-current
Commitments of the Lenders, which shall not at any time exceed $775,000,000
except as such amount may be increased pursuant to §2.2 hereof or reduced
pursuant to §2.10 hereof.











2.2.         Schedule 1.2.  Schedule 1.2 to the Credit Agreement is
hereby modified by deleting said Schedule 1.2 in its entirety and substituting
the Schedule 1.2
attached to this Agreement in place thereof.


2.3.         Acknowledgement.  The Borrower acknowledges that the increase
of the Total Commitment pursuant to this Agreement shall constitute a partial
usage of its option under §2.2 of the Credit Agreement and that after the
effectiveness of this Agreement $25,000,000 of additional increases of the
Total Commitment may be made under §2.2 of the Credit Agreement.


2.4.         Reallocation.  On the Effective Date, the Borrower shall
make such borrowings and repayments of Revolving Credit Loans as shall be
necessary to effect a reallocation of such Revolving Credit Loans in accordance
with the new Commitment Percentages of the Lenders set forth in Schedule 1.2 attached hereto.


2.5.         Fee.  The Borrower agrees to pay to the Administrative
Agent, for the account of each Lender increasing its Commitment hereunder, a
fee equal to 0.25% on the amount of the increase in such Lender’s Commitment,
which fee shall be payable on the Effective Date.


3.             Provisions
Of General Application.


3.1.         Representations
and Warranties. The Borrower hereby represents and warrants as of the
date hereof that (a) each of the representations and warranties of the Borrower
and the Guarantors contained in the Credit Agreement, the other Loan Documents
or in any document or instrument delivered pursuant to or in connection with
the Credit Agreement or this Agreement are true and correct in all material
respects as of the date as of which they were made and are true and correct in
all material respects at and as of the date of this Agreement (except to the
extent (i) of changes resulting from transactions contemplated or not
prohibited by the Credit Agreement or the other Loan Documents, (ii) of changes
occurring in the ordinary course of business, or (iii) that such
representations and warranties relate expressly to an earlier date), (b) no
Default or Event of Default exists on the date hereof (before and after giving
effect to this Agreement), and (c) this Agreement has been duly authorized,
executed and delivered by the Borrower and is in full force and effect as of
the Effective Date, and the agreements and obligations of the Borrower
contained herein constitute the legal, valid and binding obligations of the
Borrower, enforceable against it in accordance with its terms, subject only to
applicable bankruptcy, insolvency, fraudulent conveyance, reorganization,
moratorium or other laws relating to or affecting generally the enforcement of
creditors’ rights and to the fact that the availability of the remedy of specific
performance or injunctive relief is subject to the discretion of the court
before which any proceeding therefor may be brought.


The Borrower hereby
further represents and warrants as of the date hereof that the execution,
delivery and performance of this Agreement (i) are within the 











authority of the Borrower, (ii) do not conflict with
or result in any breach or contravention of any provision of law, statute, rule
or regulation to which the Borrower is subject or any judgment, order, writ,
injunction, license or permit applicable to the Borrower, (iii) do not conflict
with any provision of the agreement of limited partnership, any certificate of
limited partnership, the charter documents or by-laws of the Borrower or any
general partner or other controlling Person thereof, (iv) do not contravene any
provisions of, or constitute a default hereunder, a Default or an Event of
Default or a failure to comply with any term, condition or provision of, any
other agreement, instrument, judgment, order, decree, permit, license or
undertaking binding upon or applicable to the Borrower or any of the Borrower’s
properties (except for any such failure to comply under any such other
agreement, instrument, judgment, order, decree, permit, license, or undertaking
as would not materially and adversely affect the condition (financial or
otherwise), properties, business or results of operations of the Borrower, the
Operating Subsidiaries or any Guarantor) or result in the creation of any
mortgage, pledge, security interest, lien, encumbrance or charge upon any of
the properties or assets of the Borrower, the Operating Subsidiaries or any
Guarantor, and (v) do not require (A) the approval or consent of any
governmental agency or authority other than those already obtained, or (B)
filing with any governmental agency or authority, other than filings which will
be made with the SEC when and as required by law.


3.2.         No
Other Changes.  Except as
otherwise expressly provided or contemplated by this Agreement, all of the
terms, conditions and provisions of the Credit Agreement remain unaltered and
in full force and effect.  The Credit
Agreement and this Agreement shall be read and construed as one agreement.  The making of the modifications in this
Agreement does not imply any obligation or agreement by the Administrative
Agent or any Lender to make any other amendment, waiver, modification or
consent as to any matter on any subsequent occasion.  This Agreement shall be a Loan Document under
the Credit Agreement.


3.3.         Governing
Law.  This Agreement shall be
deemed to be a contract under the laws of the State of New York.  This Agreement and the rights and obligations
of each of the parties hereto are contracts under the laws of the State of New
York and shall for all purposes be construed in accordance with and governed by
the laws of such State (excluding the laws applicable to conflicts or choice of
law).


3.4.         Assignment.  This Agreement shall be binding upon and
inure to the benefit of each of the parties hereto and their respective permitted
successors and assigns.


3.5.         Counterparts.  This Agreement may be executed in any number
of counterparts, but all such counterparts shall together constitute but one
and the same agreement.  In making proof
of this Agreement, it shall not be necessary to 











produce or account for more than one counterpart thereof signed by each
of the parties hereto.


4.             Effectiveness
of this Agreement.  This
Agreement shall become effective on the date on which the following conditions
precedent are satisfied (such date being hereinafter referred to as the “Effective Date”):


(a)           Execution
and delivery to the Administrative Agent by each of those Lenders increasing
its Commitment, the Borrower, the Guarantors and the Administrative Agent of
this Agreement.


(b)           Execution
and delivery to the Administrative Agent of (i) a certificate of each of the
Borrower and MCRC confirming that there have been no changes to their
respective charter documents since June 22, 2007, or (ii) if there have been
changes to the Borrower’s or MCRC’s charter document since such date, a
secretary’s certificate of the Borrower or MCRC certifying as to such changes.


(c)           Delivery
to the Administrative Agent of an incumbency certificate of the Borrower and
MCRC and of resolutions of the board of directors of MCRC authorizing this
Agreement.


(d)           Payment
to the Administrative Agent, for the accounts of the Agents and the Lenders, as
applicable, all fees due and payable on or before the Effective Date and all
expenses due and payable on or before the Effective Date, including, without
limitation, reasonable attorneys’ fees and expenses and other costs and
expenses incurred in connection with this Agreement and any LIBOR Breakage
Costs payable under §4.8 of the Credit Agreement.


(e)           Delivery
to the Administrative Agent by Seyfarth Shaw LLP, as counsel to the Borrower,
and Ballard Spahr Anderson & Ingersoll, LLP, as corporate counsel to MCRC,
of opinions addressed to the Lenders and the Administrative Agent in form and
substance reasonably satisfactory to the Administrative Agent.


(f)            Execution
and delivery of the Borrower of new Notes payable to those Lenders increasing
their Commitments.


[Remainder of page
left blank intentionally]











IN WITNESS WHEREOF, the undersigned have duly executed and delivered
this Fourth Modification Agreement as of the date first set forth above.


	
  

  	
  MACK-CALI
  REALTY, L.P.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  Mack-Cali Realty
  Corporation,

  
	
   

  	
   

  	
  its general
  partner

  
	
   

  	
   

  	
   

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Barry
  Lefkowitz

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Barry Lefkowitz

  
	
   

  	
   

  	
  Title:

  	
  Executive Vice
  President

  
	
   

  	
   

  	
   

  	
  and Chief
  Financial Officer

  
					



 











 


	
  

  	
  JPMORGAN CHASE BANK, N.A., individually and 

  
	
   

  	
  as Administrative Agent, Swing Lender and Fronting

  
	
   

  	
  Bank

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Marc E. Costantino

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Marc E. Costantino

  
	
   

  	
   

  	
  Title:

  	
  Executive Director

  
					



 











 


	
  

  	
  BANK OF AMERICA, N.A.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Charlotte W. Deinhart

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Charlotte W. Deinhart

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 











 


	
  

  	
  SCOTIABANC, INC.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ J.F. Todd

  	
   

  
	
   

  	
   

  	
  Name:

  	
  J.F. Todd

  
	
   

  	
   

  	
  Title:

  	
  Managing Director

  
					



 











 


	
  

  	
  PNC BANK, NATIONAL ASSOCIATION

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ J. Richard Litton

  	
   

  
	
   

  	
   

  	
  Name:

  	
  J. Richard Litton

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 











 


	
  

  	
  CITICORP NORTH AMERICA, INC.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Niraj R. Shah

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Niraz R. Shah

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 















	
  

  	
  US BANK NATIONAL ASSOCIATION

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Walter F. Whitt

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Walter F. Whitt

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President

  
					



 











 


	
  

  	
  THE BANK OF NEW YORK

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ David Applebaum

  	
   

  
	
   

  	
   

  	
  Name:

  	
  David Applebaum

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 











 


	
  

  	
  DEUTSCHE BANK TRUST COMPANY

  AMERICAS

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Brenda Casey

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Brenda Casey

  
	
   

  	
   

  	
  Title:

  	
  Director

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ James Rolison

  	
   

  
	
   

  	
   

  	
  Name:

  	
  James Rolison

  
	
   

  	
   

  	
  Title:

  	
  Director

  
					



 











 


	
  

  	
  THE BANK OF TOKYO-MITSUBISHI UFJ, LTD.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ James T. Taylor

  	
   

  
	
   

  	
   

  	
  Name:

  	
  James T. Taylor

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 











 


	
  

  	
  NORTH FORK BANK, A DIVISION OF CAPITAL

  ONE, N.A.

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Timothy C. Thompson

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Timothy C. Thompson

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President

  
					



 











 


	
  

  	
  COMERICA BANK

  
	
   

  	
   

  
	
   

  	
  By:

  	
  /s/ Leslie A. Vogel

  	
   

  
	
   

  	
   

  	
  Name:

  	
  Leslie A. Vogel

  
	
   

  	
   

  	
  Title:

  	
  Vice President

  
					



 











 


	
  

  	
  THE ROYAL BANK OF SCOTLAND PLC

  
	
   

  	
   

  
	
   

  	
  By:

  	
   /s/ William McGinty

  	
   

  
	
   

  	
   

  	
  Name:

  	
  William McGinty

  
	
   

  	
   

  	
  Title:

  	
  Senior Vice President