Recently, a cobalt complex based electrolyte such as [Co(bpy)3]2+/3+ was suggested to replace the conventional I3 −/I− system because of its potential to provide high open circuit potential and power conversion efficiency in dye-sensitized solar cells (DSSCs). Here, a cobalt sulfide thin film was synthesized by electrochemical deposition and used for a counter electrode. A DSSC with the cobalt sulfide counter electrode exhibits J sc =7.228mA/cm2, which is 13% higher than that with Pt (J sc =6.443mA/cm2), thereby achieving an enhanced power conversion efficiency. Electrochemical impedance spectroscopy measurements indicate that the reduced Warburg diffusion impedance and faster adsorption of [Co(bpy)3]3+ facilitate the reduction of the cobalt complex.