Abstract: A novel ionic monomer 2,6-dichloropyridine N-oxide was synthesized by the oxidation of 2,6-dichloropyridine with hydrogen peroxide in trifluoroacetic acid (TFA) at 100 ℃ for 3 h. Polyimide ionomer was prepared from 2,6-dichloropyridine N-oxide, 4,4′-dimercaptodiphenyl sulfone and 4,4′-bis(4-chlorophthalimido)-3,3′dimethyldiphenylmeth (4-BCPI) in NMP at 160 ℃ for 18 h. The structures were confirmed by FTIR, and the thermal properties were characterized by differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA). Results show that the obtained polyimides exhibit excellent solubility in organic solvents including NMP, DMF, DMAc, pyridine and CHCl3. The glasstransition tempe-ratures (Tg) of these three polyimides are higher than 210 ℃.Degradation temperatures for 10% mass loss are higher than 430 ℃.