Doped polyaniline (PANI) is synthesized in aqueous HCl medium by ammonium persulphate (APS) as oxidant. We used LiCl during in situ polymerization of aniline to explore any improvement of electrical properties of PANI due to Li+ and HCl incorporation. We varied the HCl and LiCl molarity in the polymerization medium keeping the total Cl- concentration constant. The level of Li+ loading was measured by fluorescence spectroscopy of doped PANI. The PANI was characterized by FTIR and UV-visible spectroscopy, XRD analysis, intrinsic viscosity measurement and optical microscopy. The conductivity of doped PANI was measured by four probe method. Hall effect measurement was also done to measure the resistivity and the charge carrier density of the doped polyaniline. (C) 2008 Elsevier Ltd. All rights reserved.