N-Hydroxysuccinimide is widely used in bioconjugation and protein chemistry. It serves as a key reagent in the activation of carboxylic acids, enabling the formation of stable amide bonds with amines. This property makes it essential in the synthesis of peptide bonds, crosslinking agents, and labeling proteins or other biomolecules. It is commonly employed in the preparation of NHS esters, which react efficiently with primary amines under mild conditions, making it valuable in antibody-drug conjugates, fluorescent labeling, and immobilization of biomolecules on solid supports. Additionally, it plays a role in drug delivery systems and the development of diagnostic tools, where precise and stable conjugation is critical.