The metal complexes (Ru-II (phen)(2)(phendione))(PF6)(2)(1), [Ru-II (phen)(bpy)(phendione))(PF6)(2) (2), and (Ru-II (bpy)(2)(phendione))(PF6)(2) (3) (phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine and phendione = 1,10-phenanthroline-5,6-dione) have been synthesized as photo sensitizers for ZnO semiconductor in solar cells. FT-IR and absorption spectra showed the favorable interfacial binding between the dye-molecules and ZnO surface. The surface analysis and size of adsorbed dye on nanostructure ZnO were further examined with AFM and SEM. The AFM images clearly show both, the outgrowth of the complexes which are adsorbed on ZnO thin film and the depression of ZnO thin film. We have studied photovoltaic properties of dye-sensitized nanocrystalline semiconductor solar cells based on Ru phendione complexes, which gave power conversion efficiency of (eta) of 1.54% under the standard AM 1.5 irradiation (100 m W cm(-2)) with a short-circuit photocurrent density (J(sc)) of 3.42 mA cm(-2), an open-circuit photovoltage (V-oc) of 0.622V, and a fill factor (ff) of 0.72. Monochromatic incident photon to current conversion efficiency was 38% at 485 nm.