PMR type poly(benzimidazopyrrolone-imide)or poly(pyrrolone-imide)(PPI) matrix resin was synthesized using the diethyl ester of 4,4 '-(hexafluoroisopropylidene)diphthalic acid (6FDE), 3,3 ' -diaminobenzidine, para-phenylenediamine, and monoethyl ester of cis-5-norbornene-endo-2,3-dicarboxylic acid (NE) in anhydrous ethyl alcohol with N-methylpyrrolidone, The homogeneous matrix resin solution (40-50% Solid) was stable for a storage period of 2 weeks and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbon fiber-reinforced polymer composites was accomplished at optimal thermal curing conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540 degreesC. Results of MDA experiments indicate that the materials showed > 70-80% retention of the storage modulus at 400 degreesC and glass transition temperatures as high as 440-451 degreesC.