Dithienogermole-containing π-conjugated polymers were prepared by the Stille coupling reactions of distannyldithienogermole and dibromoarenes. The polymers exhibit optical properties similar to those of the previously reported silicon analogues and are usable as the active materials for bulk heterojunction-type organic photovoltaic cells as blends with PC70BM.

New dithienogermole-based conjugated polymers were synthesized by the Stille coupling reactions of distannyldithienogermole and dibromoarene, and their photovoltaic properties were studied. These polymers possess low band gaps with broad absorptions covering the 400-800 nm range, and exhibit good film forming properties. Bulk hetero-junction solar cells prepared from blends of these polymers with PC 70 BM exhibit high power conversion efficiency up to 2.38%.

Oligothiophenes end-capped with fused pyridino units were synthesized by means of the Stille coupling and their optical properties were studied. These compounds show absorption maxima and edges at 324–374 nm and 3.10–2.76 eV, respectively, depending on the oligothiophene chain lengths. DFT calculations indicate that both the HOMO and LUMO levels are lowered by the introduction of the pyridino units.