Used in bioconjugation reactions to label or modify biomolecules, particularly in click chemistry applications. The azide (N3) group reacts selectively with alkynes via copper-catalyzed or strain-promoted azide-alkyne cycloaddition, enabling efficient attachment to proteins, peptides, or nucleic acids. The PEG1 spacer enhances solubility and provides flexibility between the sugar moiety and the reactive azide, improving binding accessibility. The tetraacetylated galactopyranoside acts as a masked form of galactose, which can be deprotected under mild conditions to reveal the active sugar for interactions with lectins or glycosidases. Commonly employed in glycochemistry, drug delivery systems, and development of glycoconjugate vaccines or probes for cellular imaging.