A lactose glycosyl azide bearing a β-anomeric azide on the reducing-end glucose. The anomeric azide can be coupled to alkynes via copper-catalyzed azide-alkyne cycloaddition (CuAAC) or to DBCO and related strained alkynes via copper-free click chemistry, forming stable 1,2,3-triazole linkages. Used as a click-chemistry building block for the synthesis of lactose-presenting glycoconjugates and galectin probes.