A series of novel derivatives of 7,7'-(1,4-phenylene) bis [(5-substitutedphenyl-1,3,4-oxadiazol-2-yl)-amino (7,8-dihydropyrazino[2,3-e][1,3]oxazepine-5,9-dione)], 3a-d and 7,7'-(1,4-phenylene)bis[(5-substitutedphenyl-1,3,4-oxadiazol-2-yl)-amino (7,8 dihydro-5H-pyrazino[2,3-e][1,3]diazepine-5,9(6H)-dione)], 4a-d have been prepared by the cycloaddition reaction of 2,3-pyrazinedicarboxylic anhydride (and/or 2,3-pyrazinedicarboximide) with new derivatives of 1,3,4 oxadiazole bearing azomethine group which were prepared via cyclization reaction of some carbohydrazides with various benzoic acids in POCl3. The structures of the desired compounds were in a coincidence as deduced from their FTIR, 1H NMR, 13C NMR, and mass spectra. Antimicrobial activities of titled compounds have been recorded with good to excellent results.