A D-A-D copolymer (PBDTQx) with a bandgap of 1.78 eV, containing alkoxy-substituted benzo[1,2-b:4,5-b']dithiophene (BDT) as donor and quinoxaline derivative (Qx) as acceptor, was synthesized by Stille coupling reaction. In order to study the photovoltaic property of PBDTQx, polymer solar cells (PSCs) were fabricated with PBDTQx as the electron donor blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC61 BM) as the electron acceptor. The power conversion efficiency (PCE) of PSC was 1.01% for an optimized PBDTQx: PC61 BM ratio of 1:5, under the illumination of AM 1.5, 100 mW/cm(2). The results indicated that PBDTQx was a promising donor candidate in the application of polymer solar cells. (C) 2012 Elsevier Ltd. All rights reserved.