Poly(2,5-dimethoxyaniline) has been synthesized by cyclic voltammetry in an H2SO4-Na2SO4 solution. The facile polymer growth is due to the electron donor ability of the -OCH3 group. The polymer him behaves as an almost pure capacitor in the voltage range -0.2 to 0.5 V vs. sce. In this range, the series resistance associated with the capacitor is quite low. A maximum conductivity of 0.35 S cm(-1) has been measured at 0.2 V. The shape of the cyclic voltammetry curves is mainly determined by the capacitive character of the polymer film on which the peaks due to the main redox processes, the structural defects and the degradation reaction are superimposed. The polymer does not show a good stability in the acidic solution.