ZnS and SiO 2 –ZnS nanophosphors, with or without different concentration of Mn 2+ activator ions, were synthesized by using a sol–gel method. Dried gels were annealed at 600°C for 2h. Structure, morphology and particle sizes of the samples were determined by using X-ray diffraction (XRD), highresolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). The diffraction peaks associated with the zincblende and the wurtzite structures of ZnS were detected from as prepared ZnS powders and additional diffraction peaks associated with ZnO were detected from the annealed powders. The particle sizes of the ZnS powders were shown to increase from 3 to 50nm when the powders were annealed at 600°C. An UV–Vis spectrophotometer and a 325nm He–Cd laser were used to investigate luminescent properties of the samples in air at room temperature. The bandgap of ZnS nanoparticles estimated from the UV–Vis data was 4.1eV. Enhanced orange photoluminescence (PL) associated with 4 T 1 → 6 A 1 transitions of Mn 2+ was observed from as prepared ZnS:Mn 2+ and SiO 2 –ZnS:Mn 2+ powders at 600nm when the concentration of Mn 2+ was varied from 2–20mol%. This emission was suppressed when the powders were annealed at 600°C resulting in two emission peaks at 450 and 560nm, which can be ascribed to defects emission in SiO 2 and ZnO respectively. The mechanism of light emission from Mn 2+ , the effect of varying the concentration on the PL intensity, and the effect of annealing are discussed.