Azide-alkyne cycloaddition is a chemical reaction that combines an azide and an alkyne to form a triazole compound. This reaction is significant in click chemistry, a term coined by K. Barry Sharpless, which emphasizes simple, reliable, and efficient reactions. The process typically occurs under mild conditions and is highly selective, making it useful in various fields, including materials science and bioconjugation. The reaction proceeds through a 1,3-dipolar cycloaddition mechanism, where the azide acts as a dipole and the alkyne as a dipolarophile. This results in the formation of a five-membered ring structure. The versatility and efficiency of azide-alkyne cycloaddition have made it a popular tool for synthesizing complex molecules in organic chemistry.