Potassium dichromate initiated polymerization of aniline in acidified aqueous medium was carried out as a function of parameters such as pH, aniline/oxidant mole ratio, temperature and time. Optimum reaction conditions are outlined for the chemical synthesis of the polymer. Spectral, thermal, electrical and viscosity properties of some selective samples of polyaniline were studied. A reaction scheme has been proposed to elucidate the role of Cr(VI).