Used as a crosslinking agent in bioconjugation processes, particularly for attaching small molecules or labels to proteins and peptides. Its amine-reactive thioester group forms stable amide bonds with nucleophilic amines on biomolecules, while the sulfanyl-hexyl spacer provides flexibility and reduces steric hindrance. Commonly applied in the development of diagnostic assays, targeted drug delivery systems, and immobilization of biomolecules on surfaces. The hydrochloride salt enhances solubility in aqueous buffers, making it suitable for use in biological environments.