Riboflavin, also known as vitamin B2, is an essential water-soluble vitamin that serves as a precursor to the coenzymes flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These coenzymes participate in numerous redox reactions critical for energy metabolism, including the electron transport chain and fatty acid oxidation. It occurs naturally in eggs, dairy products, leafy vegetables, and fortified foods. The compound features a tricyclic isoalloxazine ring system responsible for its yellow-orange color and green fluorescence under UV light. Riboflavin is heat-stable but degrades rapidly upon exposure to light. It is used as a food colorant (E101) and dietary supplement. Deficiency leads to ariboflavinosis, characterized by skin disorders and anemia.