In view of various biological activities of cinnoline derivatives like antibacterial, antioxidant, antineoplastic it was our interest to prepare fluoro-pyrimido-cinnolines and then substitute it with various anilines, morpholine, piperazine and to evaluate them for antimicrobial activity. Fluoro-pyrimido-cinnoline was synthesized by reaction between 4-fluoro-3-chloro-aniline with sodium nitrite in presence of conc. HCI to form diazonium salt solution. This on treatment with ethyl cyano-acetamide gives aryl-hydrazino(cyano)acetamide which reacts with chlorobenzene in the presence of AlCl₃ to form 4-amino-3-cinnolino carboxamides which was further refluxed with formamide to give fluoro-pyrimido-cinnolines. Various fluoro-pyrimido-cinnoline derivatives were prepared by refluxing with morpholine, piperazine and substituted anilines in the presence of acetonitrile for 3-4 hours.