Herein, discovery of the first mechanism for water splitting that only requires two photons is described. Through detailed kinetic, spectroscopic and computational investigations of a molecular ruthenium complex, it was found that absorption of the first, shorter wavelength photon generates an intermediate capable of absorbing the second, longer wavelength photon. Oxygen and hydrogen can then be released. By only requiring two photons and having the ability to use a wide wavelength range, this mechanism could form the basis for the development of a new class of water splitting catalysts.