Propargyl-PEG4-CH2CH2-Boc is primarily used in bioconjugation and chemical biology research. The propargyl group allows for click chemistry reactions, particularly copper-catalyzed azide-alkyne cycloaddition (CuAAC), enabling the attachment of molecules to biomolecules like proteins, peptides, or nucleic acids. The PEG4 spacer enhances solubility and reduces steric hindrance, making it suitable for applications in drug delivery systems and the development of bioconjugates. The Boc (tert-butyloxycarbonyl) group acts as a protective group for amines, which can be selectively removed under acidic conditions, allowing for further functionalization. This compound is valuable in synthesizing targeted therapeutics, probes, and imaging agents.