Three new unsymmetric diimines L, L-Me and L-Cl were synthesized by a two-step process. Initially, the starting Schiff base 2-hydroxy-N-(5-nitrofurylidene)aniline (SB-NO2) was obtained by using 5-nitro-furfural and 2-hydroxyaniline. Nitro group of SB-NO2 was reduced into its amino derivative, SB-NH2, in solution. Diimines L, L-Me and L-Cl were obtained with the addition of 2-hydroxybenzaldehyde, 2-hydroxy-5-methylbenzaldehyde and 2-hydroxy-5-chlorobenzaldehyde, respectively, into SB-NH2 solution. Dimeric, binuclear Fe(III) and Ni(II) complexes of these ligands were also synthesized. Diimines and their complexes were characterized by elemental analyses, LC-MS, IR, electronic spectra, H-1 and C-13-NMR spectra, TGA, conductivity and magnetic measurements. The antibacterial activities of the ligands and the complexes were investigated against five bacteria. All of the compounds showed moderate activities against Escherichia coli, Bacillus subtilis and Yersinia enterecolitica. The highest activity values were obtained by Fe(III) complexes against Pseudomonas aeruginosa.