This chemical is widely used in bioconjugation and crosslinking applications due to its dual reactive groups. The azide group allows for click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling efficient and selective binding to alkyne-containing molecules. The NHS ester groups react with primary amines, making it suitable for labeling proteins, peptides, or other amine-containing biomolecules. Its PEG4 spacers enhance solubility and reduce steric hindrance, improving reaction efficiency. It is commonly employed in the development of antibody-drug conjugates, protein labeling, and the synthesis of complex biomolecular structures for research and therapeutic purposes.