A β-D-N-acetylglucosamine (GlcNAcβ) 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-N-acetylglucosamine (GlcNAcβ) building block for glycoconjugate synthesis and the construction of probes for GlcNAc-recognizing proteins and lectins; it is also relevant to O-GlcNAc and N-glycan biosynthesis research and a substrate for galactosyltransferases.