Two new Ru(II) complexes, [Ru(bpy) 2(1-COO-iqu)] + ( 2; bpy = 2,2′-bipyridine, 1-COO-iqu − = isoquinoline-1-carboxylate) and [Ru(bpy) 2(3-COO-iqu)] + ( 3; 3-COO-iqu − = isoquinoline-3-carboxylate), were prepared and their crystal structures solved. The ground and excited state properties of 2 and 3 were characterized and compared to those of [Ru(bpy) 3] 2+ ( 1). The presence of the oxygen atom in the Ru(II) coordination sphere makes 2 and 3 easier to oxidize than 1. The Ru → bpy MLCT absorption and emission of 2 and 3 are red-shifted relative to that of 1 in CH 2Cl 2, and the E 00 energies were estimated to be 1.89 eV and 1.95 eV from the low temperature emission of 2 and 3, resulting in excited state oxidation potentials of −1.03 V and −1.10 V vs SCE, respectively. In addition to the short-lived emissive 3MLCT state, a long-lived species is observed in the transient absorption of 3 in DMSO ( τ = 49 μs) and pyridine ( τ = 44 μs), assigned to a solvent-coordinated complex. This intermediate is not observed for 3 in non-polar solvents or for 2. The absence of the solvent coordinated intermediate in 2 is explained by the stronger Ru–O bond afforded by the lower conjugation in that extends onto the carboxylic acid in the 1-COO-iquo −ligand, compared to that in the 3-COO-iqu −ligand in 3. Transient absorption experiments also show that the 3MLCT excited state of 3 is able to reduce methyl viologen.