Used as a bifunctional crosslinking agent in bioconjugation, particularly for attaching fluorescent dyes, drugs, or other functional molecules to proteins, peptides, or nanoparticles. The maleimide group selectively reacts with thiol groups (-SH) under mild conditions, forming stable thioether bonds, while the two carboxylic acid groups allow further activation and coupling to amine-containing molecules via EDC/NHS chemistry. Commonly employed in the development of antibody-drug conjugates (ADCs), targeted therapies, and diagnostic probes. Its hydrophilic nature helps improve solubility and reduce aggregation in aqueous biological systems.