The encapsulation of the nanocrystalline manganese-doped zinc sulfide (ZnS:Mn) in poly(styrene-b-2vinylpyridine) (PS-PVP) diblock copolymers is reported. Below the critical micelle concentration in the absence of nanocrystals (NCs), inverse micelles of PS-PVP were induced by adding ZnS:Mn NCs, the presence of which was confirmed by scanning force microscope and dynamic light scattering. In toluene, a PS-selective solvent, the less-soluble PVP blocks preferentially surround the ligand-coated ZnS:Mn NCs. For PS-PVP encapsulated ZnS:Mn NCs, the ratio of blue emission to orange emission of ZnS:Mn NCs is dependent on both the concentration of PS-PVP and the solvent quality. The pyridine of PVP blocks form complexes with the Zn atoms via the nitrogen lone pair and thus the sulfur vacancies are passivated. As a result, the defect-related blue emission is selectively quenched even when the micelles are not formed. As the concentration of PS-PVP encapsulating the ZnS:Mn NCs increases, the intensity of blue emission decreases. (c) 2006 Wiley Periodicals, Inc.