The carboxamides are a group of chemical compounds contaning C-(O)-NH, and have various applications such as antibacterial, antitumor, drug prevention, and are also used as catalysts. Ionic liquids as new reaction media and catalysts have been experimentally and theoretically recognized and accepted. The ILs environmentally friendly or ‘‘greener’’ alternatives to organic solvents because they have very low vapor pressure and are non-explosive and thermally stable over a wide temperature range. One of the new applications of ionic liquids is in the synthesis of organic compounds including amides. Carboxamide ligands have been part of the growing research in the field of coordination chemistry of transition metal complexes. The solvent used in the justify; TEXT-INDENT: 5.65pt; MARGIN: 0cm 0cm 0pt; unicode-bidi: embed; DIRECTION: ltr; mso-pagination: widow-orphan; mso-line-height-alt: .9pt" (1) [Co(bqbenzo)] (2) [Ni(bqbenzo)] (3) [Cu(bqbenzo)] (4) [Zn(bqbenzo)] (5) [Cd(bqbenzo)] have also been synthesized and characteraized by UV-Vis, FT-IR, 1 H NMR and elemental analysis, and the antibacterial activity of the synthesized compounds has also been investigated. The structure of [Ni(bqbenzo)] and [Zn(bqbenzo)] were determined by X-ray crystallography. The di-anionic bqbenzo 2- acts as a tetradentate ligand and occupies the equatorial positions through pyridine and amide nitrogen atoms. The [Ni(bqbenzo)] has a square-planar structure distorted towards a tetrahedron. In The [Zn(bqbenzo)], with a distorted octahedral structure, two oxygen atom of amide carbonyl group from two adjacent ligand, coordinates to the axial positions of the metal ion and leads to the formation a polymeric structure for this complex situations. Nickel (II) complex was employed as a novel precursor in thermal decomposition process. The NiO nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared (IR) spectroscopy and ultraviolet–visible (UV–Vis) spectroscopy.