m-PEG9-azide is widely used in bioconjugation and click chemistry applications. Its azide group allows for efficient and selective reactions with alkyne-functionalized molecules, making it a valuable tool in the development of drug delivery systems, bioconjugates, and biomaterials. It is particularly useful in labeling proteins, peptides, and other biomolecules for research and therapeutic purposes. Additionally, its polyethylene glycol (PEG) chain enhances solubility and stability, making it suitable for modifying surfaces, nanoparticles, and hydrogels to improve biocompatibility and reduce immunogenicity. This compound is also employed in the synthesis of advanced materials and in the study of biological interactions.