The major class of organic molecules synthesis involved by the various atoms in their molecules, and they are joined in rings containing at least one atom in any synthesized compound of an element other than that of carbon atom (C). The current study aimed to synthesize the heterocyclic compound as one of the derivative N-heterocycle (I) using various complex materials and to determine their biological property in in vitro antioxidant study. Synthesis and antioxidant activities of novel Co(II), Ni(II) and Zn(II) Metal Complexes of 6-Pyridyl-5,6-Dihydrobenzo[4,5]- Imidao[1,2-C] Quinazoline (N-N) derivatives were undertaken employing a convenient and easily accessible procedure. The structures of all the synthesized compounds were confirmed with elemental analysis, IR, C13 NMR and H1NMR to know the probable structure of the molecules by stereochemistry. The synthesized five compounds were screened for in vitro antioxidant activity by 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) method. In Antioxidant studies, compound C-2 exhibited maximum inhibition (77%) at 250μg/ml concentration showing satisfactory DPPH free radical scavenging potential with the IC50 concentration at 33.61μg/ml compared to the standard drug, ascorbic acid with 6ug/ml used for the study and other compounds were also exhibited minimum antioxidant property.