Photocatalysis: The population of ligand-to-metal charge-transfer (LMCT) excited states upon light irradiation of abundant and inexpensive 3d-metal complexes represents an effective platform to access open-shell intermediates of high synthetic value. This review provides guidelines for the utilization of this inner-sphere reactivity, a comparison of its distinct profile in comparison with photoredox catalysis, and a collection of the most relevant achievements applied to organic synthesis.