Solid complexes of Schiff base (L) with Co (II), Ni (II), Zn (II), Zr (IV) and Hg (II) in acetone as a solvent were synthesised and characterised by elemental analysis, magnetic measurements, melting point, molar conductivity, FT-IR, UV–Vis., 1HNMR, X-ray diffractometer (XRD) and thermogravimetric analyses (TG and DTG). Elemental analysis is in satisfactory correlation with the proposed chemical formulae of the complexes. The estimated molar conductivity of the compounds in 1 × 10−3 M DMF solution indicates the electrolytic existence of the examinated complexes and reported as 1:2 electrolytes for Co (II), Ni (II), Zr (IV) and Hg (II) complexes and 1:1 electrolytes for Zn (II) complex. Spectral and analytical results indicate that L chelated with metal ions as bidenate through the oxygen atom of the carbonyl group and nitrogen atom of azomethine group for all complexes. The XRD patterns demonstrate the non-crystalline nature (amorphous) of the compounds (1), (4) and (5), but the compounds L, (2) and (3) lie between the amorphous and the crystalline characters. TG/DTG showed the compounds are thermally stable at room temperature and decomposed by raising the temperature to 600
C. The kinetic and thermodynamic parameters such as E*, ΔH*, ΔS* and ΔG* were calculated by using coats- Redfern and Horowitz-Metzger methods at n = 1 and n ≠ 1. Calculated values indicate more orderly activated complex formation. The measurements of the molecular modeling using density functional theory (DFT) confirm the structural geometry of the complexes, and the data showed the complexes are soft with respect to L where η varied from 0.068 to 0.077 eV and σ ranges from 12.987 to 14.706 eV, while η and σ for L are 0.109 and 9.174 eV−1, respectively. Complexes were tested for their in vitro antimicrobial activity against certain gram negative and gram positive bacteria in addition to two fungi species. The findings showed a clear increase in the anti-tuberculosis activity due to complexion.