The main challenge in the water oxidation catalysis based on Ru complexes is to develop powerful molecular anodes and photoanodes. Approximately half of thesis develops powerful water oxidation catalysts in the homogeneous phase. The other half of thesis is focused in the generation of hybrid molecular anodes and photoanodes. At the start of the thesis, we envisioned potentially seven-coordinate Ru complexes based on the [2,2′-bipyridine]-6,6′-dicarboxylate (bda2-), [2,2′:6′,2”-terpyridine]-6,6”-dicarboxylate (tda2-) and 2,5-bis(6-carboxylatopyridin-2-yl)pyrrol-1-ide  (t5a3-) ligands as equatorial ligands. Two new family of complexes that bear tda2- and t5a3- are fastest in the literature with Turn Over Frequencies up to 10 000 s-1 thanks to H intramolecular transfer. The immobilization of Ru-tda catalysts on glassy carbon electrodes coated with carbon nanotubes leads in a-million-TON-anode that sustained water oxidation catalysis without sings of degradation. Finally, a n-Si electrodes decorated with Ru-tda catalysts generated a photoanode that performed photoassisted water oxidation for over an hour.