The present communication describes the efficient synthesis of some new 7,8,9,10-tetra- hydro-1H-pyrimido[1,2- a]quinoline-2,5-dicarbonitrile derivatives via two step reaction by using a green catalytic system i.e PEG-400 and Bleaching earth clay. The structure assignments of the newly synthesized compounds based on chemical and spectroscopic evidences. All the synthesized compounds were screened for their antimicrobial activity. Most of the compounds showed significant antimicrobial activity compared with standard drugs.