The aroylhydrazone Schiff bases 2-hydroxy-(2-hydroxybenzylidene)benzohydrazide and (2,3-dihydroxybenzylidene)-2-hydroxybenzohydrazide have been used to synthesize the biand tri-nuclear Ni(II) complexes [Ni 2 (L 1 ) 2 (MeOH) 4 ] (1) and [Ni 3 (HL 2 ) 2 (CH 3 OH) 8 ]· (NO 3 ) 2 (2). Both complexes have been characterized by elemental analysis, spectroscopic techniques [IR spectroscopy and electrospray ionization-mass spectrometry (ESI-MS)], and single-crystal X-ray crystallography. The coordination behavior of the two ligands is different in the complexes: The ligand exhibits the keto form in 2, while coordination through enol form was found in 1. Herein, the catalytic activity of 1 and 2 has been compared with the nitroaldol condensation reaction under various conditions. Complex 2 exhibits the highest activity towards solvent-free conditions.Compound 2 crystallizes in the triclinic P¯1 space group. Its unit cell contains one molecule of the compound and two nitrate anions. Compound 2 is trinuclear with H 3 L 2 coordinating to the Ni(II) cations in the dianionic (HL 2 ) 2− form using both phenolate O atoms, the keto O atom, and the imine N