The article provides a comprehensive overview of flavonoids, their biosynthesis, biological functions, and biotechnological applications. Flavonoids are a diverse group of secondary metabolites found in plants, classified into six major subgroups: chalcones, flavones, flavonols, flavanols, anthocyanins, and proanthocyanidins. They play crucial roles in plant defense, UV protection, signaling, and reproduction. The biosynthesis of flavonoids involves a complex pathway that starts with the conversion of phenylalanine to 4-coumaroyl-CoA, followed by the action of chalcone synthase and other enzymes. Genetic engineering has been used to modify flavonoid biosynthesis in plants, leading to the production of novel colors and compounds. Additionally, combinatorial biosynthesis techniques have been developed to produce flavonoids in microorganisms, offering potential for industrial applications. The article also discusses the regulatory mechanisms of flavonoid biosynthesis, including the role of transcription factors and the importance of metabolic channels. Finally, it highlights future challenges and questions in the field, emphasizing the need for further research to understand the full extent of flavonoid biology and their applications.The article provides a comprehensive overview of flavonoids, their biosynthesis, biological functions, and biotechnological applications. Flavonoids are a diverse group of secondary metabolites found in plants, classified into six major subgroups: chalcones, flavones, flavonols, flavanols, anthocyanins, and proanthocyanidins. They play crucial roles in plant defense, UV protection, signaling, and reproduction. The biosynthesis of flavonoids involves a complex pathway that starts with the conversion of phenylalanine to 4-coumaroyl-CoA, followed by the action of chalcone synthase and other enzymes. Genetic engineering has been used to modify flavonoid biosynthesis in plants, leading to the production of novel colors and compounds. Additionally, combinatorial biosynthesis techniques have been developed to produce flavonoids in microorganisms, offering potential for industrial applications. The article also discusses the regulatory mechanisms of flavonoid biosynthesis, including the role of transcription factors and the importance of metabolic channels. Finally, it highlights future challenges and questions in the field, emphasizing the need for further research to understand the full extent of flavonoid biology and their applications.