A β-D-galactose ligand equipped with a primary amine through a hydrophilic PEG3 spacer. The amine couples with NHS-activated esters to form stable amide bonds, providing a route to conjugate the ligand onto NHS-activated molecules and surfaces. 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.