A β-D-glucose ligand equipped with a terminal carboxylic acid through a hydrophilic PEG3 spacer. The carboxylic acid can be activated to NHS, sulfo-NHS, or pentafluorophenyl esters and reacted with amine-functionalized platforms or lysine residues on proteins and peptides to form amide bonds. This compound provides a β-D-glucose building block for glycoconjugate synthesis, glycomimetic research, and the construction of probes for glucose-recognizing proteins and lectins.