An initial and laser irradiated poly( bis-alkylthioacetylene) was investigated at X-band (9.6 GHz), K-band (37 GHz), and D-band (140 GHz) EPR in a wide temperature region. Two types of paramagnetic centers were proved to exist in laser modified polymer, namely localized and mobile polarons whom both concentration ratio and susceptibility depend on the irradiation dose and temperature. Superslow torsion motion of the polymer chains was studied by the saturation transfer method at 2-mm waveband EPR. Additional information on the polymer chain segment dynamics was obtained by the spin probe method at X-band EPR. Spin-spin and spin-lattice relaxation times were measured separately using steady-state saturation method at the 2-mm waveband EPR. Intrachain and interchain spin diffusion coefficients and conductivity coming from polaron dynamics were calculated. It was shown that the conductivity of laser modified polymer is determined by strong spin-spin interaction and is stimulated by torsion motion of the polymer chains. The total conductivity of PATAC is determined mainly by dynamics of diamagnetic charge carriers. Magnetic, relaxation and dynamics parameters of PATAC was also shown to change during a storage of the polymer.