A photoelectrochemical cell was designed that catalyzes the photooxidation of water using visible light as the sole energy source and a molecular catalyst, [Mn4O4L6](+) (1(4), L = bis(methoxyphenyl)phosphinate), synthesized from earth-abundant elements. The essential features include a photochemical charge separation system, [Ru-II(bipy)(2)(bipy(CCO)(2))]. adhered to titania-coated FTO conductive glass, and 1(+) embedded within a proton-conducting membrane (Nafion). The complete photoanode represents a Functional analogue Of the water-oxidizing center of natural photosynthesis.