It has been reported that in oxo-bridged systems having the Ru-O-Ru moiety, chemically significant interactions exist between the Ru atoms through the bridging ligand.Such compounds manifest unusual physical and chemical properties. This is possibly as a result of the strong Ru-O-Ru interaction which makes the separate Ru3+ ions lose their identity since the valence levels which largely determine these properties are molecular orbitals delocalised over the Ru-O-Ru linkage. The oxo-bridged ruthenium dimer has been synthesised, characterised and a lot of kinetic data have been documented as regards its redox behaviour with some reducing agents such as l - cysteine,glutathione, iodide, sulphite, 2 - mercaptoethanol and 2- mercaptoethylamine, ascorbic acid,bromate and 1, 4- benzenediol. Further work on the redox behaviour of diaquotetrakis(2,2'- bipyridine) - mi - oxodiruthenium (III) ion is important due to the versatility of the ruthenium dimer for their potential use in diverse areas such as photosensitizers for photochemical conversion of solar energy.