The synthesis, characterization, and catalytic performance of the new sulfonic acid supported on the magnetic nanoparticles with maghemite coating were reported. The morphology, particle size, structure, magnetic properties, and the formation of nanoparticles with narrow size distribution were investigated. Chemical analysis was performed by using TEM, wide-angle XRD, FTIR spectroscopy, and X-ray fluorescence, and magnetic measurements were performed by using vibrating sample magnetometry. The catalyst was found to be active for the synthesis of pyrroles. The nanometer size range of these particles facilitates the catalytic process owing to the increased surface area available for the reaction. The easy separation of the catalyst by an external magnet from liquid-phase reactions and its usability for at least nine consecutive trials without any decrease in activity are additional advantages.