Hexagonal ZnS nanorods (L×W=∼60nm×∼4nm and surface area=59.1m2g−1) and cubic ZnS nanoflowers (diameter=∼70nm and surface area=65.2m2g−1) like nanocrystals have prepared and investigated their relative optical and photocatalytic properties for the selective reduction of (m, p)-dinitrobenzene to (m, p)-nitroaniline. The band edge absorption at 325nm (3.72eV) of nanoflowers, 354nm (3.52eV) of nanorods are significantly red-shifted, and photoluminescence is notably quenched after 1wt% Au and Pt loading due to exciton–Plasmon’s interactions. It revealed for the first time that bare and Au/Pt deposited ZnS nanostructures exhibited highly improved photocatalytic activity for the selective reduction of (m, p)-dinitrobenzene to (m, p)-nitroaniline (>90 yield) formation under UV (125WHgarc, 10.4mW/cm2) light irradiation for 8h. This observed photoactivity is attributed to the size and shape dependent changes in band edge position relative to bulk ZnS, suitable reduction potential (−0.48eV) of NO2 group and favorable Fermi energy/electron accepting states of Au/Pt lying below the conduction band position of as-prepared ZnS nanoparticles.