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This thesis describes recent progress in electrochemical preparation of several conducting polymers. In particular, the synthesis and characterizations of pure polyaniline, pure polypyrrole, polyaniline/polypyrrole and polypyrrole/polyaniline copolymers and polyaniline-polypyrrole physical blends were studied. The focus has included firstly synthesis of these electrically conductive polymers. Secondly, thermal characteristics of electrochemically synthesized homopoly- mers, copolymers and their physical blends were investigated by thermal gravi- metric analysis (TGA), differential scanning calorimetry (DSC) and direct pyrol- ysis mass spectrometry (DIP-MS) techniques. In general, TGA analysis showed three-step thermal degradation. The first, at 100oC, was attributed to water, and unreacted monomers. The second weight losses observed at around 150 oC was because of evolution of water and/or acid. Finally, the removal of the dopant ion and low molecular weight species from the matrix were observed for pure PANI and pure PPy at 230 and 280 oC, respectively. PANI/PPy films and PPy/PANI films have decomposition temperatures at 272oC because of the loss of the dopant ion. It was also observed that pure PPy was thermally more resistant than pure PANI. Thirdly, thermal characteristics, and degradation products of electrochemi- cally prepared PANI/PPy and PPy/PANI films in solutions containing variable dopant (SO42&amp / #8722 / ) concentrations were analyzed and compared with pyrolysis mass spectrometry. Similar to TGA study, there were three main thermal degradation steps namely, evolution of low molecular weight species, dopant based products and degradation products of polymers. The dopant concentration was monitored to optimize the degradation behavior. Pyrolysis mass spectrometry data showed that the degree of degradation of the polymer already coated on the electrode enhanced as the dopant concentration used in synthesis increased.