Ag[1-butyl 3-methyl imidazolium]Br nanospheres were prepared by a coprecipitation method at ambient temperature. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffusion reflectance spectra (DRS), the Brunauer_Emmett_Teller (BET) nitrogen adsorption–desorption isotherms, and Fourier transform infrared spectroscopy (FT-IR) analysis methods. The photocatalytic properties were evaluated by degradation of acid blue 92 (AB92) and rhodamine B (RB) dye solutions under visible light and the obtained results were discussed. According to the recycling experiments, the samples could efficiently decrease the concentration of the pollutant after four times of repeated using. To assure the practical capacity, photodegradation of a real wastewater produced in the textile industry was studied under the same conditions and the results indicated that the absorption in all wavelengths reduced impressively by the photocatalytic treatment. Furthermore, the antimicrobrial activity was investigated by photoinactivation of S. aureus bacteria in the visible light and the results implied that the prepared samples were able to prevent the growth of bacteria colonies after the reaction time.