We report in this work the synthesis and spectroscopic, electrochemical, spectroelectrochemical, and photophysical characterization of a novel series of ruthenium polypyridyl complexes with 4-methyl-2,2'-bipyridine-4'-carbonitrile (Mebpy-CN) as an auxiliary ligand of general formula [Ru(bpy)(3-x)(Mebpy-CN)(x)](PF6)(2) (x = 1-3) (with bpy = 2,2'-bipyridine). A significant increase in the lifetime and quantum yield of emission of the lowest (MLCT)-M-3 excited state is disclosed when going from x = 1 to x = 3, evidencing an improvement of the photosensitizing properties with respect to [Ru(bpy)(3)]-(PF6)(2). Furthermore, quenching by molecular oxygen of (MLCT)-M-3 excited states of the three complexes produced singlet molecular oxygen (O-1(2)) with quantum yield values higher than that of [Ru(bpy)(3)](2+) in CH3CN. The structure of the complex with x = 1 has been determined by X-ray diffraction. The photoconductivity of ZnO nanowires covered with this same complex is increased by an order of magnitude, pointing to its feasibility as a component of a DSSC. A new dinuclear complex with Mebpy-CN as a bridging ligand has also been prepared and characterized by physicochemical techniques. The derived mixed-valent species of formula [(bpy)(2)Ru-II(Mebpy-CN)Ru-III(NH3)(5)](5+) displays a considerable metal-metal electronic coupling due to the delocalization effect of a nitrile group in the 4' position of the bpy ring.