To overcome the limitation of a single photon excitation, one may learn from nature which for instance uses four photons of visible light cumulatively for the challenging task of water oxidation in the process of photosynthesis. A similar concept, consecutive photoinduced electron transfer (con-PET) has recently been introduced to synthetic chemistry. Here, two approaches have been described to cumulate the energy of two photons of visible light to carry out thermodynamically challenging transformations (Figure ). On the one hand, electron transfer to an excited photocatalyst followed by exciting the just singly reduced photocatalyst generating a strong reductant excited species (Figure ) and on the other hand photosensitised triplet formation of the photocatalyst that forms via triplet-triplet annihilation of two triplets one excited singlet and one ground state photocatalyst, where the former also represents a high reductive excited species (Figure ).