The poly-o-toluidine (POT) was prepared under different magnetization in solution containing 0.5 mol dm(-3) o-toluidine, 1.0 mol dm(-3) HCI with and without 0.5 mol dm(-3) DyCl3, respectively. Their conductivity, UV-vis, FTIR spectra, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) were investigated. The results of conductivity showed that magnetic field and the cooperative effect of Dy3+ and magnetic field do obvious effect to conductivity of POT. Meantime, they also can make the energy for the pi-pi transitions and quinoid ring transition in UV-vis spectra smaller. At high magnetization the peaks of POT due to Q-NH+-B or B-NH+-B and C-H out of plane on 1,4-ring or 1,2,4-ring disappeared in FTIR spectra. Magnetic field and Dy3+ can make three dimensions morphologies of the POT clear, but they scarcely affect the crystallinity of POT. (c) 2007 Wiley Periodicals, Inc.