n-Conjugated poly(hydroquinone)s and poly(p-benzoquinone)s have been prepared, and their optical and redox behaviors have been studied. Poly(hydroquinone-2,5-diyl),PPP-2,5-OH, with a weight-average molecular weight of 8500 (determined by the light scattering method) was soluble in DMF. The pi-pi* absorption peak of hydroquinone at 296 nm is shifted to 345 nm in PPP-2,5-OH. PPP-2,5-OH underwent electrochemical two-step oxidation at about 0.5 and 0.8 V versus Ag/Ag+. Another type of poly(p-hydroquinone)s in an acetylenic main chain was also prepared, and the polymer underwent oxidation with the first oxidation peak at about 1.0 V versus Ag/Ag+. Optical and X-ray diffraction data of the polymers and their precursor polymers suggest stacking of the polymer molecules.