Used in bioconjugation reactions to link biomolecules such as peptides, proteins, or nucleic acids with other functional groups due to the reactive propargyl group, which readily participates in click chemistry, especially copper-catalyzed azide-alkyne cycloaddition (CuAAC). The PEG2 spacer enhances solubility in aqueous and organic solvents, reduces aggregation, and improves bioavailability by increasing the distance between conjugated molecules, minimizing steric hindrance. The mesylate (Ms) group serves as a good leaving group, enabling nucleophilic substitution reactions to attach the molecule to amines or thiols, making it useful in the development of antibody-drug conjugates (ADCs), targeted therapies, and diagnostic probes. Also employed in surface modification and functionalization of materials for biosensors or microarrays.