Encouraging developments in the field of photocatalysis in last decades, biomolecules namely flavins have been observed to act as a catalyst in several photoredox-catalysed synthetic methodologies. Due to its excellent redox window and good chemical stability, this promising photoactive biological molecule has emerged as a powerful and attractive metal-free organophotocatalyst. This review highlights the design, properties, biosynthesis and application of flavin photoredox catalysts and is expected to contribute to a great extent towards the advancement and development of synthetic methodologies.