This compound is widely used in bioconjugation chemistry, particularly for attaching biomolecules like proteins, peptides, or antibodies to other molecules or surfaces. Its azide group allows for efficient click chemistry reactions, such as the copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling the creation of stable triazole linkages. The NHS ester group reacts with primary amines, making it ideal for labeling or modifying amine-containing biomolecules. The PEG spacer enhances solubility and reduces steric hindrance, improving reaction efficiency and biocompatibility. Applications include drug delivery systems, surface functionalization, and the development of diagnostic tools or biosensors. It is also valuable in proteomics and antibody-drug conjugate (ADC) research for precise and controlled conjugation.