The homo- and co-poly(p-phenyene ether sulfone benzimidazole/sulfide sulfone benzimidazole)s (PESI/PPSSI) had been prepared by solution polycondensation of the mixtures of 4,4′-dicarboxydiphenyl ether (DCDPE) and 4,4′-dicarboxydiphenyl sulfide (DCDPS) with 3,3′,4,4′-tetraanmino diphenyl sulfone (TADS) in polyphosphoric acid (PPA). The FT-IR, 1H-NMR, DSC, TGA, XRD were used to characterize chemical structure and thermal stabilities of the resultant homo- and co-polymers. The inherent viscosities of the resultant polymers were in the range of 0.621–0.982 dl/g at the polymer concentration of 0.5 %. They were found to have excellent thermal properties with glass transition temperatures (Tg) of 386–393 °C, 5 % weight-loss temperature (T5%) of 512–525 °C. These polymers showed amorphous nature as charactered by XRD. Most importantly, the resultant polymers possess good solubility that they can be soluble in various aprotic solvents such as N-methyl-2-pyrolidinone (NMP), dimethyl sulfoxide (DMSO) and 1,3-dimethyl-2-imidazolidinone (DMI) and they could be easily formed transparent, tough and flexible membranes by solution casting method. The membranes showed good mechanical properties: the tensile strengths and Young’s Modulus were in the range of 68.8–98.6 MPa and 2.1–2.8 GPa, respectively.
