Used as a key reagent in organic synthesis, particularly in cyclopropanation reactions through metal-catalyzed decomposition. It transfers diazo groups to alkenes, forming cyclopropane derivatives important in pharmaceuticals and agrochemicals. Also employed in the preparation of β-lactams and other heterocyclic compounds via X-H insertion reactions (X = O, N, S). Its ability to generate carbenes under mild conditions makes it valuable in constructing complex molecular architectures. Handle with care due to explosive and toxic properties.