ZnS nanostructures have been synthesized by simple wet chemical route and annealed at two different temperatures of 50°C and 180°C. From the measurements of transmission electron microscopy and contact-mode atomic force microscopy, it is found that annealed temperature changes the morphology from nanoparticles to nanorods. The optical properties of the synthesized ZnS nanomaterial have been characterized by UV–visible absorption spectroscopy and photoluminescence spectroscopy. The structural and elemental analyses were carried out by powder X-ray diffraction pattern and energy dispersive X-ray absorption spectroscopy, respectively. Absorption edge of the nanoparticles (295nm) and nanorods (326nm) was shifted towards shorter wavelength compared to bulk ZnS (337nm) due to the quantum confinement effect.