The luminescence of nanocrystalline ZnS : Mn2+ without a doubt displays a brief decay time part (?100 ns), and also a long (ms) decay time is noticed. The limited decay time is ascribed to a defect-relevant emission of ZnS, and isn't in the decay with the transition in the Mn2+ impurity. The transition on the Mn2+ has a `typical??decay of about one