Bromoacetamide-PEG3-propargyl is a heterobifunctional linker used in bioconjugation and click chemistry applications. The bromoacetamide moiety enables selective attachment to thiol groups on cysteine residues in biomolecules through nucleophilic substitution. Its propargyl group facilitates efficient copper-catalyzed azide-alkyne cycloaddition (CuAAC) for conjugating with azide-functionalized molecules, making it valuable for labeling proteins, peptides, or other biomolecules. The PEG3 spacer improves water solubility and reduces steric hindrance, enhancing reaction efficiency. It is particularly useful in drug delivery systems, diagnostic assays, and the development of targeted therapies.