This chemical is widely used in bioconjugation and drug delivery systems. It acts as a linker molecule, connecting drugs, peptides, or proteins to other molecules, such as polymers or nanoparticles. The NHS ester group enables efficient coupling with amine-containing compounds, while the PEG4 spacer enhances solubility and reduces steric hindrance, improving the stability and bioavailability of the resulting conjugates. It is particularly valuable in the development of targeted therapies, antibody-drug conjugates, and diagnostic agents, where precise and stable molecular linkages are essential. Additionally, its application extends to surface modification of materials for biomedical research and biosensor development.