NUMBER

               

              U-__________

               

            	 	 	 	
              UNITS

            
	
              SEE
                REVERSE FOR CERTAIN DEFINITIONS

            	
              TREMISIS
                ENERGY ACQUISITION CORPORATION
                II

            


    

     

    CUSIP
      89472N 200

    


    UNITS
      CONSISTING OF ONE SHARE OF COMMON STOCK AND ONE WARRANT EACH TO PURCHASE ONE
      SHARE OF COMMON STOCK

    


    THIS
      CERTIFIES THAT
      _________________________________________________________________________________________

    


    is
      the
      owner of
      ______________________________________________________________________________________
      Units.

    


    Each
      Unit
      (“Unit”) consists of one (1) share of common stock, par value $.0001 per share
      (“Common Stock”), of Tremisis Energy Acquisition Corporation II, a Delaware
      corporation (the “Company”), and one warrant (the “Warrant(s)”). Each full
      Warrant entitles the holder to purchase one (1) share of Common Stock for $6.00
      per share (subject to adjustment). Each Warrant will become exercisable on
      the
      later of (i) the Company’s completion of a merger, capital stock exchange, asset
      acquisition or other similar business combination and (ii) ___________, 2008,
      and will expire unless exercised before 5:00 p.m., New York City Time, on
      ____________, 2012, or earlier upon redemption (the “Expiration Date”). The
      Common Stock and Warrants comprising the Units represented by this certificate
      are not transferable separately prior to __________, 2007, subject to earlier
      separation in the discretion of Merrill Lynch, Pierce, Fenner & Smith
      Incorporated. The terms of the Warrants are governed by a Warrant Agreement,
      dated as of _______, 2007, between the Company and Continental Stock Transfer
      & Trust Company, as Warrant Agent, and are subject to the terms and
      provisions contained therein, all of which terms and provisions the holder
      of
      this certificate consents to by acceptance hereof. Copies of the Warrant
      Agreement are on file at the office of the Warrant Agent at 17 Battery Place,
      New York, New York 10004, and are available to any Warrant holder on written
      request and without cost. 

     

    This
      certificate is not valid unless countersigned by the Transfer Agent and
      Registrar of the Company.

     

    Witness
      the facsimile seal of the Company and the facsimile signatures of its duly
      authorized officers.

     

    By

    
      
        	
                 

              	
                 

              	
                 

              
	
                 
                  

              	
                  

              	
                 
                  

              
	
                Chairman
                  of the Board  

              	
                 Secretary

              
	
                 

              	
                 

              


      

    

     

    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    Tremisis
      Energy Acquisition Corporation II

     

    The
      Company will furnish without charge to each stockholder who so requests, a
      statement of the powers, designations, preferences and relative, participating,
      optional or other special rights of each class of stock or series thereof of
      the
      Company and the qualifications, limitations, or restrictions of such preferences
      and/or rights. 

     

    The
      following abbreviations, when used in the inscription on the face of this
      certificate, shall be construed as though they were written out in full
      according to applicable laws or regulations:

    
      


      
        	 	
                TEN
                  COM -

              	
                as
                  tenants in common

              	
                UNIF
                  GIFT MIN ACT -

              	
                _________
                  Custodian __________

              
	 	
                TEN
                  ENT -

              	
                as
                  tenants by the
                  entireties      

              	 	
                (Cust)
                  

              	
                (Minor)

              
	 	
                JT
                  TEN -

              	
                as
                  joint tenants with right of survivorship

              	 	
                under
                  Uniform Gifts to Minors

              
	 	 	
                and
                  not as tenants in common   

              	 	
                Act
                  __________________

              
	 	 	
              	 	
                (State)

              


      

       

    

    Additional
      Abbreviations may also be used though not in the above list.

     

    For
      value received, ___________________________ hereby sell, assign and transfer
      unto

    


    PLEASE
      INSERT SOCIAL SECURITY OR OTHER

    IDENTIFYING
      NUMBER OF ASSIGNEE

     

    
      
        

      

    

    
      


    

    
      
        

      

    

    _______________________________________________________________________________________________________________________
(PLEASE
      PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF
      ASSIGNEE)

     

    _______________________________________________________________________________________________________________________


    _______________________________________________________________________________________________________________________


    _____________________________________________________________________________________________________
      Units

     

    represented
      by the within Certificate, and do hereby irrevocably constitute and
      appoint

    


    ______________________________________________________________________________________________  Attorney

    to
      transfer the said Units on the books of the within named Company will full
      power
      of substitution in the premises.

    


    Dated
      _______________ 


     

    
      	 	 	 

	 	
              Notice:

            	
              
                The
                  signature to this assignment must correspond with the name as written
                  upon
                  the face of the certificate in every particular, without alteration
                  or
                  enlargement or any change
                  whatever.

              

            


    

     

    Signature(s)
      Guaranteed:

     

    _____________________________________________________________________________

    THE
      SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR
      INSTITUTION

    (BANKS,
      STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH

    MEMBERSHIP
      IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM,

    PURSUANT
      TO S.E.C. RULE 17Ad-15).