Bromo-PEG5-ethyl phosphate is widely utilized in bioconjugation and chemical biology research. Its primary application lies in modifying biomolecules, such as proteins, peptides, and nucleic acids, to enhance their solubility, stability, and functionality. The compound is particularly useful in the development of drug delivery systems, where it acts as a linker to attach therapeutic agents to targeting molecules, improving their specificity and efficacy. Additionally, it is employed in the synthesis of functionalized nanoparticles and polymers for biomedical applications, including imaging, diagnostics, and targeted therapy. Its PEG (polyethylene glycol) moiety reduces immunogenicity and prolongs circulation time in biological systems, making it valuable in creating biocompatible materials.