Advances in visible-light-mediated photo redox catalysis have created an exceptional approach for small-molecule activation and new chemical bond formation in organic synthesis. This is an alternative technique to generate new reactive intermediates and enable distinct synthetic strategies that were previously unthinkable. Of the many trademarks, photochemistry is often classified as “green” technology, promoting organic reactions under mild conditions without the necessity for potent and wasteful solvents, oxidants and reductants. This mini review covers the overview of the primary principles of photoredox catalysis, discussing various metal-based and organophotocatalysts. It further surveys a variety of reactions, including trifluoromethylation, cyanation, C-H functionalizations, supramolecular catalysis, and heterogeneous catalysis in both aqueous and alcoholic mediums.