New ruthenium(II)-polypyridyl complexes la (X=H) and lb (X=Cl) having 2,6-bis(4-carboxyquinolin-2-yl)pyridine derivatives were synthesized as a sensitizer for dye-sensitized solar cells (DSCs), and their photophysical and photochemical properties were characterized. Both of the complexes showed broad electronic absorption bands in the near-IR region, which were assigned to the metal-to-ligand charge transfer (MLCT) transitions. On the other hand, the photovoltaic performance of the DSCs sensitized with them were different from each other. The DSC sensitized with la exhibited higher IPCE value than that of the one sensitized with lb. The substituent effects on the ligand on photovoltaic performance of the DSCs were examined. (c) 2010 Elsevier B.V. All rights reserved.