An optimized synthetic protocol toward highly reactive Rieke zinc is applied for the preparation of a series of omega-(2,5-dibromothiophene-3-yl)alkyl acetate monomers and statistical copolythiophenes derived thereof, with 10% of ester-functionalized side chains. The obtained conjugated polymers are attractive electron donor materials for organic solar cells, notably to increase the thermodynamic stability of the bulk heterojunction polymer:fullerene active layer blend, and are fully characterized by a combination of spectroscopic, thermal analysis and electrochemical techniques. (C) 2013 Elsevier Ltd. All rights reserved.