A multicomponent reaction (MCR) is a chemical process where three or more reactants combine to form a single product or a set of products in one step. This type of reaction is efficient because it reduces the number of steps needed in synthesis, saving time and resources. MCRs are widely used in organic chemistry to create complex molecules, including pharmaceuticals and natural products. These reactions often involve the formation of multiple bonds and can lead to diverse chemical structures. Common examples of MCRs include the Biginelli reaction, which synthesizes dihydropyrimidinones, and the Ugi reaction, which produces α-amino acids. MCRs are valuable tools in modern synthetic chemistry.