Melanin is to the animal kingdom like chlorophyll to the vegetal kingdom(1). Melanin collects energy from lower-energy radiation sources, kicks electrons into excited states, initiating a process that would end up producing chemical energy, similar to the way in which photosynthesis supplies energy to plants. However, the precise roles of melanin during this process are unknown. Here we show that the increase in the electron-transfer properties of melanin is independent of the energy of the incident photons. We found in controlled in vivo assays that melanin has the remarkable capability of converting lower-energy radiation towards a more useful form of energy. Furthermore, we found that melanin can break up water molecules and giving up energy suggesting an additional behavior mode for melanin. Our results demonstrate how members of the melanin family are likely to function as transducers, oxidizing water, pushing apart water molecules, as well as recruiting back ions into molecules that are subsequently polarized again. Melanin drives the photon energy of lower-energy radiation sources by quenching electrons and initiating an ionic event independently of their relative energy contention. We anticipate our assay to be a starting point for more sophisticated photoelectrochemical applications. For example, the individual and combined action of multiple photovoltaic applications could be tested, including conducting polymers, for example poly-(phenylenevinylene) (PPV) derivatives or C60 particles. Furthermore, melanin's energy conversion ability is a major target of solar energy conversion development, and an organic-semiconductor way for photoelectrochemical applications will be relevant for such developments.</sup></sup>
