Polyaniline and ring substituted polyanilines were prepared by chemical oxidation and characterized by elemental and IR analyses, esr studies, wide-angle x-ray diffractometry and electroconductivity measurement. IR spectra of the polymers show the coexistence of benzenoid and quinoid structures. Relatively strong esr signals indicate that the polymers have free spins. According to the electroconductivities measured, steric and inductive effects of the substituents play important roles, in a rather complicated manner, in controlling electrical properties of HCl-or I₂-doped polymers. Conductivity decreases in the order of the substituent X=H>OCH₃>CH₃>Cl>C₆H₅ for HCl-doped compositions and X=H>Cl>OCH₃ CH₃ for I₂-doped ones. With the exception of the C₆H₅-substituted polymer, conductivity at room temperature of HCl-doped compositions ranges from 2×10^-7 to 3×10^-1Ω^-1cm^-1 and that of I₂-doped ones from 3×10^-3 to 4×10^-2Ω^-1cm^-1. It also was observed that doping with I₂ drastically destroys the crystallinity of the polymers.