This paper presents the synthesis, MO calculations, and photochemical and photophysical properties of cis-[Ru(bpy)(2)(3Amdpy(2)oxaNBE)](PF6)(2) , where bpy is 2,2'-bipyridine and 3Amdpy(2)oxaNBE is the novel 5,6-bis(3-amidopyridine)-7-oxanorbornene chelate-ligand . Complex is considered in relation to the cis-[Ru(bpy)(2)(3Amnpy)(2)](PF6)(2) analogous complex, where 3Amnpy is 3-aminopyridine. Complexes exhibit absorptions near 350 nm and in the 420-500 nm region attributable to a contribution from MLCT transitions (d(pi) -> bpy and d(pi) -> L; L = 3Amdpy(2)oxaNBE or 3Amnpy). Whereas complex is photochemically reactive, complex shows luminescence either at 77 K or at room temperature in fluid solution. The emission of assignable as an MLCT (Ru -> bpy) emission is characterized by a long lifetime at room temperature (650 ns in CH3CN and 509 ns in H2O). It is independent of lambda(irr), but it is temperature dependent; i.e., it increases as the temperature is lowered. Considering the chelate ring of contributes to the stability of the complex under continuous light irradiation, the difference in the primary photoprocesses of (loss of 3Amnpy) and (luminescence) may be caused by a lowering of the lowest excited state from. The surface crossing to the lowest MC state value of 987 cm(-1) (similar to that of [Ru(bpy)(3)](2+)) will be prevented in the case of complex , and as a result, efficient 3Amdpy moiety loss cannot occur. The electronic depopulation of the {Ru(bpy)(2)} unit and population of a bpy* orbital upon excitation are evident by comparing the photophysical properties with those of a [Ru(bpy)(3)](2+) related complex. Moreover, a reduction of a bpy ligand in the MLCT excited state is indicated by time-resolved spectra that show features typical of bpy(center dot-). The photocatalytic property of is spectroscopically demonstrated by oxidative quenching using either methylviologen(2+) or [RuCl(NH3)(5)](+2) electron-acceptor ions.