Exhibit 4.1


 


	
    NUMBER

     

    U-__________
	
     

    
	UNITS
	 

                                                                                SEE REVERSE FOR
 CERTAIN DEFINITIONS
	

                                                                                 

                                                                                CLEANTECH ACQUISITION CORP.
	 


 


CUSIP [_]


 


UNITS CONSISTING OF ONE SHARE OF COMMON STOCK,
ONE RIGHT AND ONE-HALF OF A WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK


 


THIS CERTIFIES THAT


 


is the owner of                                                                                                                                                                                     
Units.


 


Each Unit (“Unit”) consists of one
share of common stock, par value $0.0001 per share, of CleanTech Acquisition Corp., a Delaware corporation (the “Company”),
one right and one-half of a warrant. Each holder of a right is entitled to receive one-twentieth of one share of common stock of the Company
upon the Company’s completion of a merger, share exchange, asset acquisition, stock purchase, recapitalization, reorganization or
other similar business combination, with one or more target businesses (a “Business Combination”). Each warrant entitles the
holder to purchase one share of common stock of the Company at $11.50 per full share (subject to adjustment), upon the later to occur
of (i) the Company’s completion of a Business Combination or (ii) 12 months from the closing of the Company’s initial public
offering (the “IPO”). Each warrant expires 5 years after the completion of our initial Business Combination, at 5:00 p.m.,
New York City time, or earlier upon redemption or liquidation.


 


The common stock, rights and warrants comprising
the Units represented by this certificate are not transferable separately until the 90th day after the date of the prospectus relating
to the IPO, unless Chardan Capital Markets, LLC informs the Company of its decision to allow earlier separate trading, provided that the
Company has filed with the Securities and Exchanges Commission a Current Report on Form 8-K, which includes an audited balance sheet reflecting
the Company’s receipt of the gross proceeds of the IPO.


 


The terms of the rights are governed by a rights
agreement (the “Rights Agreement”), dated as of [_], 2021, between the Company and Continental Stock Transfer & Trust
Company, as the rights 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.


 


The terms of the warrants are governed by a warrant
agreement (the “Warrant Agreement”), dated as of [_], 2021, between the Company and Continental Stock Transfer & Trust
Company, as the 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 Rights Agreement and the Warrant
Agreement are on file at the office of the rights agent and warrant agent at 1 State Street, 30th Floor, New York, New York 10004, and
are available to any right or warrant holder on written request and without cost.


 


Each Unit may be mandatorily split by the Company
in connection with the closing of a Business Combination.


 


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


 


This Unit Certificate shall be governed and construed
in accordance with the internal laws of the State of New York, without regard to conflicts of laws principles thereof.


 


Witness the facsimile signatures of its duly authorized
officers.


 


By:


 


	 	 	 
	Chairman	 	Secretary


 




     


     


    

 


CleanTech Acquisition Corp.


 


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 shares 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 sells, assigns and transfers 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 with full power of substitution in the premises.


 






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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) MUST 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).	 


 


As more fully described in the Company’s
final prospectus dated of [•], 2021, the holder of this certificate shall be entitled to receive funds with respect to the underlying
share of common stock from the trust account established in connection with the Company’s initial public offering only in the event
of the Company’s liquidation upon failure to consummate a business combination within the required time period set forth in the
Company’s Amended and Restated Certificate of Incorporation (the “Certificate”), as the same may be amended from time
to time, or if the holder seeks to convert his or her respective shares of common stock underlying the Unit upon consummation of such
business combination or in connection with certain amendments to the Certificate. In no other circumstances shall the holder have any
right or interest of any kind in or to the trust account.


 


 


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