It was established that the reaction of sodium thiosulfate with poly(p-phenylenediamine)poly(1,4-benzoquinonediimine-N,N-diyl-1,4-phenylene) and its derivative with acetylated end amino groups results in 1,4-addition of thiosulfate to quinonediimine groups. The same reaction was investigated with its model compound N,N-di(4-acetaminophenyl)-1,4-benzoquinonediimine. The reaction conditions for high conversion of quinonediimine groups were worked out. Electrical conductivity of obtained polymers was less than 10(-10) S/cm and was increased with doping level increase up to 2.8x10(-6)S/cm when doping with iodine.