ABSTRACT. The reaction between benzil and hexamethylenediamine formed a new ligand [L], [(1Z,3Z)-2,3-diphenyl-5,6,7,8,9,10-hexahydro-1,4-diazecine], of the type [N2], was synthesized by the condensation reaction through Schiff base reaction between benzil and hexamethylenediamine. The new Schiff base ligand reacts with Mnп, Niп and Coп metal ions to give the complexes with the general formula: [M(L)Cl2]. The elemental investigations have been used to analyze the ligand and its complexes by CHN, FT-IR, UV-Vis, TLC, mass spectrum, melting point with the study of biological activity to the formed compounds. From the data obtained, the proposed molecular structure adopts square planar structure about the metal ions. The study reveals the formation of a new ligand type [N2] and it's metal ion complexes with square planar structures metal:ligand ratio of 1:1, which can be employed in a variety of fields such as medicine and industry.     KEY WORDS: Benzil, Hexamethylenediamine, Metal complexes, Square planar structure   Bull. Chem. Soc. Ethiop. 2022, 36(4), 791-799.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i4.6