Propargyl-PEG12-bromide is widely used in bioconjugation and chemical synthesis due to its unique properties. Its propargyl group enables click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), making it valuable for attaching molecules like proteins, peptides, or drugs to PEGylated platforms. The PEG12 spacer enhances solubility and reduces immunogenicity, making it ideal for drug delivery systems and improving the pharmacokinetics of therapeutic agents. Additionally, it serves as a versatile linker in the development of biomaterials, diagnostics, and targeted therapies, where precise molecular attachment and biocompatibility are essential. Its bromide group further allows for functionalization or substitution reactions, expanding its utility in organic synthesis and material science.