Schiff bases 2,3-butanedione bis{(iso)nictonioylhydrazone} were obtianed by 2,3- butanedione condensation with hydrazides of nicotinic or isonicotinic acids. Iron and cobalt coordination compounds were synthesized by interaction of metal salts with Schiff bases respectively, as well through template reaction between metal salts, 2,3–butanedione and nicotinic or isonicotinic acides hydrazides. High lability of NH groups hydrogens of Schiff bases molecules and pH value of the reaction medium determines the composition of obtained complexes. Iron(III) forms compounds of type [Fe(H2L)X2]X∙nY and [Fe(H2L)(H2O)2]X3∙nY (X = NO3-, ClO4-, NCS-, N3-; Y=H2O, HNO3) in acidic medium. Infrared spectra of coordination compounds with iron are distinguished by the presence of bands at 3194 cm-1, ν(NH) and at ~1632 cm-1, coordinated ν(C=O). If NCS- groups are present then the high intensity band of ν(C≡N) appears at ~2055 cm-1 and are assigned as oscillations of those groups in coordinated ligands through nitrogen atom or anions in external coordination sphere. N3- anions display a singular band of high intensity at ~2050 cm-1, which corresponds to N3- anions oscillations coordinated monodentate to metal or anions from external coordination sphere. Several absorption of high intensity bands were observed in the IR spectra of iron(III) complexes with NO3- groups, in the range 1400-1200 cm-1, indicating the presence of NO3- groups, possessing different potential functions: coordination to iron atom, as anions in the external coordination sphere and as nitric acid. The IR spectra of complexes which contain ClO4- group present absorption bands: ν(NH) peaked at ~3200 cm-1, ν(C=O) coordinated at ~1616 cm-1 and a wide and very intensive band in the range 1150-1000 cm-1 with absorption maximum at 1080 cm-1, assigned to the ClO4- group oscillations. The wide band of average intensity in the range 2800-2300 cm-1 is assigned to oscillations of C=NH+ groups, constituted by protonated heterocyclic nitrogen atoms. Thus iron(III) complexes have most likely an octaedric structure, which ecuatorial plane is constituted by Schiff base molecule coordinated through N2O2 sets of atoms and the axial coordinate is located along oxygen (water, nitrate) or nitrogen (NCS-, N3-) atoms. In cobalt coordination compounds with Schiff bases, the metal has mostly oxidation state +2, octaedric structure and forms complexes of non-electrolyte type – [Co(H2L)X2] (X=OH-, NCS-, N3-, NO3-). The spectra of cobalt complexes synthesized in acidic medium contain distinct bands ν(NH) at ~3196 cm-1, and ν(C=O) coordinated at ~1630 cm-1. Absorption bands of NCS-, N3-, NO3- groups appear in spectra as two bands in the range 2114-2075 cm-1, 2075-2018 cm-1 and 1306 cm-1, respectively. High value of ν(C≡N) suggests that NCS- groups less likely form anions in the external coordination sphere, however the coordination mode, through nitrogen or sulfur atoms is impossible to confirm, since absorption bands appear in the overlap region, in which we could identify these two coordination modes of NCS- groups, specifically M-NCS or M-SCN. In alkaline medium, Schiff bases coordinate in enolic form. In the spectra of iron(III) and cobalt(II) complexes, absorption bands ν(NH) and ν(C=O) could not be identified, however a very intensive band appears at ~1384 cm-1, which presumably contains ν(C−O) oscillations generated by enolization of Schiff bases.