With the objective to convert light energy into chemical oxidation energy, a ruthenium-based dyad constituted of the assembly of a photosensitizer and a catalytic fragment was synthesized. Upon irradiation with blue LEDs, and in the presence of an electron acceptor, the complex is able to catalyze selective sulfide oxygenation involving an oxygen atom transfer from water to the substrate. Electrochemical and photophysical studies highlighted a proton-coupled electron transfer (PCET) to access to a high valent oxidant Ru(IV) oxo species.