The article introduces the concept of "Click Chemistry," a modular, process-driven approach to molecular synthesis that emphasizes the rapid and reliable formation of carbon-heteroatom bonds. This approach is inspired by nature's preference for forming carbon-heteroatom bonds over carbon-carbon bonds, as seen in the synthesis of biomolecules like nucleic acids, proteins, and polysaccharides. The authors define Click Chemistry reactions as those that are modular, have a wide scope, yield high products, generate non-chromatographic byproducts, and are stereospecific. They highlight the importance of simple reaction conditions, readily available starting materials, and the use of water or benign solvents. The article discusses various types of Click Chemistry reactions, including nucleophilic opening of epoxides and aziridines, cycloadditions, and carbonyl/imine condensation reactions. It also emphasizes the advantages of using water as a solvent, which allows for reliable and clean sequential transformations. The authors provide examples of Click Chemistry sequences for creating diverse molecular frameworks, such as the rapid assembly of steroid-like skeletons and the synthesis of diverse heterocyclic structures. They argue that Click Chemistry offers a more efficient and modular approach to drug discovery and combinatorial library synthesis, avoiding the complexities and inefficiencies of traditional carbonyl-based synthesis.The article introduces the concept of "Click Chemistry," a modular, process-driven approach to molecular synthesis that emphasizes the rapid and reliable formation of carbon-heteroatom bonds. This approach is inspired by nature's preference for forming carbon-heteroatom bonds over carbon-carbon bonds, as seen in the synthesis of biomolecules like nucleic acids, proteins, and polysaccharides. The authors define Click Chemistry reactions as those that are modular, have a wide scope, yield high products, generate non-chromatographic byproducts, and are stereospecific. They highlight the importance of simple reaction conditions, readily available starting materials, and the use of water or benign solvents. The article discusses various types of Click Chemistry reactions, including nucleophilic opening of epoxides and aziridines, cycloadditions, and carbonyl/imine condensation reactions. It also emphasizes the advantages of using water as a solvent, which allows for reliable and clean sequential transformations. The authors provide examples of Click Chemistry sequences for creating diverse molecular frameworks, such as the rapid assembly of steroid-like skeletons and the synthesis of diverse heterocyclic structures. They argue that Click Chemistry offers a more efficient and modular approach to drug discovery and combinatorial library synthesis, avoiding the complexities and inefficiencies of traditional carbonyl-based synthesis.