Semiconductor ZnS with novel and complex 3D architectures such as nanorods (or nanowires) networks, urchinlike nanosturctures, nearly monodisperse nanospheres self-assembled from nanorods and 1D nanostructures (rods and wires) had been synthesized in a binary solution by controlling the reaction conditions, such as the volume ratio of the mixed solvents and the reaction temperature. The morphology of ZnS changed from 3D architectural structures to ID rodlike (or wirelike) shape when the temperature was increased from 160 to 200-240 degrees C. The possible growth mechanisms for the formation of nanospheres self-assembled from nanorods are tentatively discussed according to the experimental results. The photocatalytic activity of carious ZnS nanostructures has been tested by degradation of acid fuchsine under infrared light compared to that of commercial ZnS powders under infrared-light irradiation and commercial TiO2 powders under UV-light irradiation, indicating that the as-obtained ZnS nanostructures exhibit excellent photocatalytic activity for degradation of acid fuchsine.