Used in bioconjugation processes, particularly in the development of antibody-drug conjugates (ADCs). Its main function is to link antibodies to cytotoxic agents through stable yet cleavable bonds. The pyridyldithio group enables reversible disulfide bond formation, allowing controlled release of the drug in targeted cells. Commonly applied in pharmaceutical research for site-specific labeling of proteins and peptides. Also utilized in immobilizing biomolecules on surfaces for diagnostic assays and biosensors due to its NHS ester reactivity with primary amines.