Used extensively in bioconjugation and click chemistry, Bromo-PEG5-azide serves as a bifunctional linker to attach biomolecules or functional groups. The bromide group allows for nucleophilic substitution reactions, such as with thiols or amines, enabling conjugation to proteins, peptides, or other nucleophilic biomolecules. Its azide group enables efficient reactions with alkynes via copper-catalyzed azide-alkyne cycloaddition (CuAAC), making it valuable in drug delivery systems, polymer modification, and surface functionalization. The PEG5 (polyethylene glycol) spacer enhances solubility, reduces immunogenicity, and improves biocompatibility, making it suitable for applications in biopharmaceuticals, diagnostics, and material science. It is particularly useful in creating targeted therapeutics and imaging agents by facilitating the attachment of targeting moieties or labels to biomolecules.