Polyquinones [poly(2-methylanthraquinone-1,4-diyl) [P(2Me-1,4-AQ)], poly(anthraquinone-1,4-diyl) [P(1,4-AQ)], etc.] having pi-conjugation systems along their main chains have been prepared by an organometallic dehalogenation polycondensation of the corresponding dichloroquinones. P(2Me-1,4-AQ) is soluble in various organic solvents and has a molecular weight of 190 000 as determined by a light scattering method. Casting from solutions of P(2Me-1,4-AQ) gives films with good optical and mechanical quality. Chemical reductions of P(2Me-1,4-AQ) in N-methyl-2-pyrrolidone (NMP) with N2H4 and Na2S2O4 lead to the formation of a dianion (Q(2-)) and dihydrogenated species (QH(2)) of the quinone unit (Q), respectively. On the other hand, chemical reduction of P(2Me-1,4-AQ) with a mixture of Na2S2O4 and NaOH in NMP is interpreted by a stepwise mechanism involving formation of an intermediate radical-anion species (Q(.-)). Cyclic voltammogram of the P(2Me-1,4-AQ) film exhibits two redox cycles with E(1) degrees and E(2) degrees values of -1.38 and -1.69 V vs Ag/Ag+ corresponding to quinone/radical anion (Q/Q(.-)) and radical anion/dianion (Q(.-)/Q(2-)) redox couples, respectively. Reduction of P(2Me-1,4-AQ) and P(1,4-AQ) with sodium naphthalenide gives semiconducting materials.