Difurfurylidenecyclopentanone (DFCPN) and dicinnamylidene cyclopentanone (DCCPN) were synthesized by aldol condensation reactions of cyclopentanone with furfural and cinnamaldehyde, both derived from renewable resources. The DFCPN and DCCPN were prepolymerized with 4,4'-bismaleimidodiphenylmethane (BMI) at 190 degrees C and then compression molded at 250 degrees C to produce cured DFCPN/BMI and DCCPN/BMI resins (DFCPN-BMI and DCCPN-BMI) with a molar ratio of 1/1, 1/2 or 1/3. The FT-IR spectral analysis of the cured resins and FD-MS analysis of the model reaction products using N-phenylmaleimide revealed that maleimide-rich addition copolymerization occurred. All of the cured resins except DCCPN-BMI 1/1 exhibited glass transition temperatures higher than 350 degrees C and 5 % weight loss temperatures higher than 450 degrees C, and their values increased with increasing BMI content. When cured resins with the same molar ratio were compared, DFCPN-BMI exhibited a higher flexural strength than DCCPN-BMI. Especially, DFCPN-BMI 1/1 exhibited extremely excellent flexural properties and heat resistance.