Undoped and (Ni, Co, and Mn)-doped ZnS nanoparticles (NPs) are successfully synthesized by a  sonochemical assisted co-precipitation technique. XRD patterns reveal the incorporation of dopant ions by substitution of Zn
ions. Ni ions induce growth rate enhancement and the increase of crystallite size, whereas Co and Mn ions slow
down the growth rate and caused the decrease of the corresponding crystallite size. The UV–visible absorption
spectra exhibit a decrease in the optical band gap for all doped samples. The photoluminescence spectra of Co and Mn-doped ZnS NPs show an improvement in the visible light, whereas Ni-doping results in a slight decrease
in the emission intensity allover the spectral range. The room-temperature ferromagnetism of ZnS NPs is strongly
improved by Ni- and Co-doping and slightly enhanced by Mn-doping. The AC conductivity of ZnS NPS is
enhanced by Ni- and Co-doping and decreased by Mn-doping in the frequency range from 2 kHz to 1 MHz.