Effect of electrolyte during electrochemical synthesis of polycarbazole (PCz) is reported in this paper. Two different supporting electrolytes tetrabutylammonium perchlorate (TBAClO(4)) and tetrabutylammonium tetrafluoroborate (TBABF(4)) dissolved in acetonitrile are used for the synthesis of PCz. The electrolyte effect with regard to yield, structure, electroactivity, crystallinity and thermal stability of the polymer is studied through various techniques including XRD, cyclic voltammetry, differential scanning calorimetry and electrochemical impedance spectroscopy. High doping and facilitation of dopant ion movement in the case of PCz/fBAClO(4) in comparison to PCz/TBABF(4) film is revealed in conductivity measurements and electrochemical investigations. XRD shows a significant difference in the crystallinity of the polymers synthesized using in two different electrolytes. Melting point of the conducting polymer is also observed for the first time during thermal investigations (in case of PCz/TBABF(4)). The amorphous to crystalline transformation of PCz is also observed on heating. A comparative analysis of both the electrolytes also shows that TBAClO(4) is a better supporting electrolyte than TBABF(4) in various aspects for synthesis of PCz. (C) 2010 Elsevier B.V. All rights reserved.