Magnetic, relaxation, and dynamic parameters of polarons P₁^.+, trapped in p-toluenesulfonic acid doped polyaniline, polarons P₂^.+, and fullerene radical anions photoinduced in the poly(3dodecylthiophene)/methanofullerene composite and in mixtures of these composites have been investigated using the EPR technique. It has been shown that spin charge carriers P₂^.+ during diffusion along poly(3dodecylthiophene) chains interact with P₁^.+ trapped on adjacent polymer chains of polyaniline. The exchange interaction and spin relaxation in the ternary composites is determined by the activated hopping mobility of polarons P₁^.+ and depends on the composition of the material.