Exhibit 4.2


 





 


UNLESS THIS CERTIFICATE IS PRESENTED BY
AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE CORPORATION OR
THE TRANSFER AGENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF [   ] OR IN SUCH OTHER NAME AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO [   ], OR TO SUCH OTHER ENTITY AS IS REQUESTED
BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS
WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, [   ] HAS AN INTEREST HEREIN. TRANSFERS OF THIS GLOBAL SECURITY
SHALL BE LIMITED TO TRANSFERS IN WHOLE, BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH SUCCESSOR’S
NOMINEE.


 


THE CORPORATION IS AUTHORIZED TO ISSUE
MORE THAN ONE CLASS OF STOCK AND MORE THAN ONE SERIES OF ITS CLASS OF PREFERRED STOCK. THE CORPORATION WILL FURNISH WITHOUT CHARGE
TO EACH STOCKHOLDER WHO SO REQUESTS THE POWERS, DESIGNATIONS, PREFERENCES AND RELATIVE PARTICIPATING, OPTIONAL OR OTHER SPECIAL
RIGHTS OF EACH CLASS OF STOCK OR SERIES THEREOF AND THE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND/OR
RIGHTS.


 


 




     

     


    

 


Incorporated under the laws of the State
of Delaware, June 24, 1996


 


Certificate Number: [     ]


Initial Number of Shares of Series A Convertible Preferred Stock:
[     ]


 


 


	 	CUSIP [     ]
	 	ISIN [     ]
	 	 


 


CELLECTAR BIOSCIENCES, INC.


 


Cellectar Biosciences, Inc. (the “Corporation”)
hereby certifies that [     ] (the “Holder”) is the registered owner of [     ]
fully paid and non-assessable shares of the Corporation’s designated Series A Convertible Preferred Stock, par value $0.00001
per share (the “Series A Preferred Stock”), transferable on the books and records of the Transfer Agent, in
person or by a duly authorized attorney, upon surrender of this certificate duly endorsed or assigned and in proper form for transfer.


 


This Certificate and the shares represented
hereby are issued and shall be held subject to all the provisions of the Second Amended and Restated Certificate of Incorporation
and the Amended and Restated Bylaws of the Corporation and any amendments thereto, including the provisions of the Certificate
of Designation of Preferences, Rights and Limitations of Series A Convertible Preferred Stock, dated _________, 2016, as the same
may be amended from time to time (the “Certificate of Designation”). Capitalized terms used herein but not defined
shall have the meaning given them in the Certificate of Designation.


 


The shares of the Series A Preferred Stock
shall be convertible in the manner and accordance with the terms set forth in the Certificate of Designation.


 


Reference is hereby made to the provisions
of the Series A Preferred Stock set forth in the Certificate of Designation, which provisions shall for all purposes have the same
effect as if set forth at this place.


 


Upon receipt of this executed certificate,
the Holder is bound by the Certificate of Designation and is entitled to the benefits thereunder.


 


Unless the Transfer Agent has properly countersigned,
these shares of the Series A Preferred Stock shall not be entitled to any benefit under the Certificate of Designation or be valid
or obligatory for any purpose.


 




     

     


    

 


IN WITNESS WHEREOF the said Corporation
has caused this Certificate to be signed by its duly authorized officer as of _________, 2016.


 





	 	 
	 	By: 	 
	 	Name: 

Title: 
	 	 	 


 


 


 


 


 



     

     


    




 




COUNTERSIGNATURE


 


These are shares of the Series A Convertible
Preferred Stock referred to in the within-mentioned Certificate of Designation.


 


Dated: _________, 2016


 


American Stock Transfer & Trust Company, LLC, as Transfer
Agent


 


 


	 	 
	 	By: 	   ____________________________________________________
	 	Name:

Title:
	 	 	 


 


 




     

     


    

 


NOTICE OF CONVERSION


 


(To
be Executed by the Registered Holder in order to Convert Shares of Preferred Stock)


 


The undersigned hereby elects to convert
the number of shares of Series A Convertible Preferred Stock indicated below into shares of common stock, par value $0.00001 per
share (the “Common Stock”), of Cellectar Biosciences, Inc., a Delaware corporation (the “Corporation”),
according to the conditions hereof, as of the date written below. If shares of Common Stock are to be issued in the name of a Person
other than the undersigned, the undersigned will pay all transfer taxes payable with respect thereto. No fee will be charged to
the Holders for any conversion, except for any such transfer taxes.


 


Conversion calculations:


 


	
        Date to Effect Conversion: _____________________________________________

         

	
        Number of shares of Preferred Stock owned
        prior to Conversion: _______________

         

	
        Number of shares of Preferred Stock to
        be Converted: ________________________

         

	
        Stated Value of shares of Preferred Stock
        to be Converted: ____________________

         

	
        Number of shares of Common Stock to be
        Issued: ___________________________

         

	
        Applicable Conversion Price:____________________________________________

         

	
        Number of shares of Preferred Stock subsequent
        to Conversion: ________________

         

	
        Address for Delivery: ______________________

         

        Or

         

        DWAC Instructions:

        Broker no: _________

        Account no: ___________



 


	 	
         

        [HOLDER]

         

        By:___________________________________

        Name:

        Title: