Used as a bifunctional crosslinking agent in bioconjugation, particularly for coupling peptides or proteins with other biomolecules. Its structure contains two active ester groups that react efficiently with primary amines under mild conditions, enabling stable amide bond formation. Commonly applied in the preparation of antibody-drug conjugates (ADCs) and labeling of proteins with fluorescent dyes or biotin. Also utilized in immobilizing biomolecules onto surfaces such as biosensors or microarrays due to its hydrophilic nature and controlled reactivity.