The development of an alternative promoter system for thioglycoside activation comprising N-iodosuccinimide (NIS) and acid-washed molecular sieves (AW-300 MS) has been studied and found to mediate high-yielding coupling with a variety of glycosyl acceptors. The utility of this combination is further exemplified by its application to reactivity-based coupling of thioglycosides and sequential one-pot regioselective glycosylation.