(2S,4S)-H-L-Pro(4-N3)-OH (hydrochloride) functions as a reagent in click chemistry. This form of chemistry is celebrated for its potential applications in the conjugation of nucleic acids, lipids, proteins, and other molecules, owing to its high yield, specificity, and simplicity. The compound features an Azide group that can undergo copper-catalyzed azide-alkyne cycloaddition reactions (CuAAC) with molecules containing Alkyne groups. Additionally, it can participate in strain-promoted azide-alkyne cycloaddition reactions (SPAAC) with molecules that possess DBCO or BCN groups.