High-throughput methodology, as used in pharmaceutical drug discovery, was successfully applied to high performance polyimide development. Using a Biotage(R) microwave reactor fitted with a flask handling robot and a high-throughput approach, we have optimized a copolyimide material with high T-g, yet maintaining solution processability. Additionally, the development time for this material has been reduced from months to just weeks. The polyimide was produced using combinations of the monomers 4,4'-ODA, 6-FDA and PMDA. The optimal combination was found to be 2:1:1 of 4,4'-ODA/6-FDA/PMDA with a molecular weight (MW) of 31 500 and T-g of 347 degrees C. The resulting polymer can be solution-cast into strong, flexible membranes for solution and gas phase separations.