[Ru(tmtacn)(R(2)bpy)(OH2)](2+) (tmtacn = 1,4,7-trimethyl-1,4,7-triazacyclononane; R(2)bpy = 4,4'-disubstituted-2,2'-bipyridines, R = H, Me, and OMe) with tmtacn ligated in a facial fashion is found to be active as O-2-evolving catalysts. It is also found that the stronger electron-donating character of R(2)bpy gives rise to the higher O-2-evolving activity.