degree of polymerization and is such that the inherent viscocity of the polymer is within the range of about 0 2 to about 1 0 when determined as a 1 solution at 25 u00b0 c in n methyl 2 pyrrolidinone str4 wherein 0 01 u2266 x u2266 0 99 and x equals the molar ratio of bibenzyl 4 sulfone units present in the total polymer weight z is selected from the group consisting of a direct link oxygen sulfur lower alkylidene or lower alkyl other than ethylene having from about 1 to 5 carbon atoms str5 wherein 0 01 u2266 x lt x y u2266 0 99 and y equals the molar ratio of str6 units present in the total polymer weight and z 1 is a member of z different than the specific z group present in the polymer typical ab polymers corresponding to the above formulas include polybibenzyl sulfone formula i copolymers of bibenzyl sulfone copolymerized with biphenyl sulfone z is a direct link or diphenyl ether sulfone z is oxygen said copolymers containing at least 1 mole per cent of bibenzyl sulfone units formula ii and terpolymers of bibenzyl sulfone copolymerized with two different aromatic sulfone units such as biphenyl sulfone z is a direct link and diphenyl ether sulfone z 1 is oxygen said terpolymers also containing at least 1 mole percent of bibenzyl sulfone units formula iii it should be evident that suitable copolymers containing more than three different aromatic sulfone units would also be within the scope of this invention it is also possible to prepare so called aabb type polymers by the condensation reaction of approximately stoichiometric quantities of one of the 4 4 39 disulfonyl chloride.