Multi-component reactions (MCRs) are strong synthetic tools in which more than two starting materials are coupled together with a purpose to form the multi-functionalized compounds in a one-pot process. In this procedure, they used an additional step without changing the solvent, the so-called sequential-addition procedure, to limit the number of synthetic steps while increasing the complexity and the molecular diversity, which are highly step-economical reactions. The Ugi reaction, one of the most common multi-component reactions, has recently fascinated chemists with the high diversity brought by its four-or three-component-based isonitrile. The Ugi reaction has been introduced in organic synthesis as a novel, efficient and useful tool for the preparation of libraries of multifunctional peptides, natural products, and heterocyclic compounds with stereochemistry control. © 2021, Dr. Yashwant Research Labs Pvt. Ltd.. All rights reserved.