The interfacial polymerization of aniline at aqueous/IL has been conducted. The product was characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, thermal gravimetric analysis (GTA), and electrical conductivity measurement. In this route, both solvents used are environmentally benign and polyaniline (PANI) particles with diameters from about 30-80 nm can be fabricated. We believe that this method can be used to synthesize some other useful polymers. ((C))2004 Elsevier Ltd. All rights reserved.