The remarkable attributes of light as a clean, selective, and potent energy source for facilitating chemical reactions have fueled the field of organic photochemistry for over a century (Figure ). Ciamician, in 1912, advocated the use of light to facilitate chemical transformations, marking a groundbreaking moment in the field's evolution. The field remained fairly dormant except for seminal works in the 1970s and 1980s by Kellog , Fukuzami and Tanaka , and Pac for the reduction of organic substrates by Ru II -dihydropyridine catalytic system and Cano-Yelo and Deronzie's work for oxidation reactions. In 2008, the field of organic photochemistry experienced a paradigm shift towards photoredox catalysis when Yoon, Macmillan, and Stephenson independently published reports of photoredox catalysis that solved distinct synthetic challenges. Since then, a variety of photoredox catalysts have emerged, including transition metal catalysts, inorganic semiconductors, organic molecules, hybrid systems, and newer platforms in continuous development.