This chemical is primarily utilized in bioconjugation and chemical biology research, where it serves as a linker or spacer molecule. The azide group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), which is widely used for labeling, modifying, or crosslinking biomolecules such as proteins, peptides, and nucleic acids. The PEG4 (polyethylene glycol) spacer provides flexibility and solubility, enhancing the efficiency of the conjugation process while minimizing steric hindrance. This makes it valuable in drug delivery systems, where it can be used to attach therapeutic agents to targeting molecules. Additionally, it is employed in the development of biosensors and diagnostic tools, facilitating the attachment of detection moieties to biological substrates. Its versatility and compatibility with aqueous environments make it a useful tool in various biochemical and biomedical applications.