Photoredox chemistry, a catalytic approach to harvesting visible light energy, provides a way out of this conundrum. In pioneering work in 2011 it was shown that benzene oxidation can be carried out photocatalytically to produce phenols with oxygen as a terminal oxidant. Subsequently a new reactivity paradigm for selective oxidative functionalization of arenes under mild conditions was established. However, such systems are confined to the energy of a single photon of visible light, e.g. 440 nm (2.82 eV, 65 kcal/mol), which limits their oxidative power. For example, the energy of excited state acridinium photocatalysts are lower than +2.5 V vs. SCE (saturated calomel electrode), which is insufficient to remove an electron from an electron deficient arene. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as the only photocatalyst capable of reaching > +3 V vs. SCE is unstable, toxic, and reacting with water as well as with nucleophiles to release poisonous HCN gas. Furthermore, it has to be used in stoichiometric or sub-stoichiometric amounts, which limits its applicability. Thus, alternative systems are highly desirable.