Used as an active ester reagent in peptide synthesis and bioconjugation processes. It efficiently couples amines under mild conditions, forming stable amide bonds. Commonly employed in the preparation of protein-protein or protein-polymer conjugates, especially in pharmaceutical development. Its structure allows for controlled release of the active group, minimizing side reactions. Also utilized in solid-phase synthesis due to its stability and solubility characteristics. Suitable for labeling biomolecules with fluorescent tags or functional probes where high reactivity and selectivity are required.