Novel A-D-A type oligothiophenes incorporating benzothiadiazole (BTDA) and thiadiazolopyridine (TDAPy) as terminal acceptor groups have been developed for smallmoleculeorganicsolarcells (SMSC). In vacuum-processed planar heterojunction solarcells the TDAPy-based oligomer showed a power conversion efficiency of 3.15% and a high fill factor of 0.67.