1, 4-Diazabicyclo [2.2.2] octane (DABCO) was employed as a catalyst for one-pot synthesis of pyrano[2,3-d] pyrimidinone derivatives and MWNT- pyrimidinones from condensation reactions of aromatic aldehydes, malononitrile and thiobarbituric acid and MWNT-COCl . This method delivers the advantages of a simple method, environment friendly procedure, mild reaction conditions and high returns. The m...