Synthesis of chlorine containing polysilanes by catalytic redistribution is described and the obtained polymers are characterized by infrared (IR)-, magic angle spinning nuclear magnetic resonance (MAS-NMR)-spectroscopy and elemental analysis. The pyrolysis of such polysilanes was investigated by thermoanalysis, IR-, MAS NMR- and electron spin resonance (ESR)-spectroscopy. The conversion process from polysilane into polycarbosilane is described in terms of the results of the performed investigations and a model of the process is developed. Differences between this conversion process and those for chlorine free polysilanes or polycarbosilanes previously described by other authors are discussed.