Polyvinyl chloride (I), polyvinylidene chloride (II) and further chlorinated products of polyvinyl chloride (III) can be completely dehydrohalogenated if appropriate conditions are chosen. The elementary analyses of the products fit the formula (CH)n. The infrared spectra and x‐ray diffraction patterns indicate that the structure of the products is similar to that of noncrystalline, trans‐polyacetylene. The absorption band due to CHCH (trans) is observed for all products; for the products from (II) and (III), the band due to CC also appears. All products show paramagnetic properties. The highest value of specific resistivity is about 104 ohm‐cm.