A β-D-galactose ligand equipped with a terminal alkyne through a hydrophilic PEG3 spacer. The alkyne couples to azide-functionalized partners via copper-catalyzed azide-alkyne cycloaddition (CuAAC), forming stable 1,2,3-triazole linkages. This compound provides a β-anomeric galactose building block for glycoconjugate synthesis, glycomimetic research, and the construction of probes for galactose-recognizing proteins, including galectins and other lectins. Terminal β-Gal residues are also a substrate for glycosyltransferases, including sialyltransferases and fucosyltransferases.