AbstractIn this paper, five new zinc‐Schiff base compounds formulated as ZnLX2 (L is a new N3‐Schiff base ligand obtained by condensation reaction between diethylenetriamine and (Z)‐3‐(4‐(dimethylamino)phenyl) acrylaldehyde and X is (Cl−, Br−, I−, N3−, and NCS−)) were synthesized and characterized by Fourier transform infrared, 1H and 13C NMR, UV–visible, thermal analyses, and molar conductivity measurements. Low molar conductivity values of the compounds in dimethylformamide (DMF) showed nonelectrolyte character of them. Zinc complexes have been also prepared in nanostructure sizes under ultrasonic irradiation confirmed by X‐ray powder diffraction and scanning electron microscopy. Thereafter, ZnO nanoparticles were prepared by direct calcination process of zinc iodide complex at 600°C under air atmosphere. Furthermore, thermogravimetric analyses of the complexes were used for the investigation of thermal behavior of the tiled compounds. Based on TG/DTG plots, some kinetics activation parameters of the compounds at all thermal decomposition steps were calculated. In final, antimicrobial activities of the compounds were investigated by the well diffusion technique against the gram‐positive bacteria of Staphylococcus aureus and Bacillus subtilis, and the gram‐negative bacteria of Escherichia coli and Pseudomonas aeruginosa and the fungi strains of Aspergillus oryzae and Candida albicans. The results showed that all zinc‐Schiff base organic compounds are more antimicrobial active than free ligand.