Four metal complexes of antibacterial agent lomefloxacin (LFX) with zirconium(IV) in the presence of aniline (An), pyridine (Py) and o-tolidine (o-Tol) as nitrogen donor molecules and dimethyl formamide (DMF) as oxygen donor molecule have been prepared and characterized with physicochemical and diverse spectroscopic techniques (IR, UV-Vis. and 1H NMR spectroscopes) as well as thermal analysis. The deprotonated lomefloxacin complexes of Zr(IV) were isolated as solids with the general formula, [ZrO(LFX)2L]Cl2,where L = An, Py, o-Tol and DMF. The infrared spectral data show the chelation behavior of LFX toward Zr(IV) through oxygen of pyridone, one oxygen of carboxylic group and complete the coordination number with nitrogen or oxygen atom of L. The thermodynamic parameters are calculated from the thermal analysis curves using the Coats–Redfern and Horowitz–Metzger methods. The antibacterial of LFX and their Zr(IV) complexes were also evaluated for their antibacterial activity against three Gram (+Ve) and three Gram (-Ve) microorganisms.