In previous studies it has been shown that [Cr2(OH)2(nta)2]2¯ and [Cr2(m-OH)(m-Ac)(nta)2]2¯ manifested as mono- and polydentate ligands, due to their specific structural characteristics.In a continuation of the previous studies, we has focused on the diversification of the chromium(III) dimeric building blocks with the perspective to use in the design of then 1D-3D coordination polymers [1, 2]. By using homogeneous aqueous mixtures of [Cr2(OH)2(nta)2]2¯ and formic, acetic, cyanoacetic, benzoic or iso-nicotinic acids, the anions of Cr(III) in solution were obtained at concentration 1.10-3 M of reactants. Determination of the end of the reactions in solutions was performed by UV-Vis spectrophotometry in time. The Figure shows, that the characteristic peaks of Cr(III) ions, in the {NO5} environment, formed from nta3- and 2OH¯ ligands, the characteristic peaks at 408.1 nm and 584.2 nm (Figure, blue line) shifts to higher energy values, and does not differ from the spectrum of the combination [(m-H2O)3{Pb(H2O)2}2{Cr2(m-OH)(m-Ac)(nta)2}2]-14H2O (Figure, red line) described in [2]. Thereby, we can assume, that in solution the [Cr2(mOH)2(nta)2]2¯ reacts with the respective carboxylic acids with formation of new complexes, similar to the [Cr2(m-OH)(mAc)(nta)2]2¯ anions. To confirm thishypotheses, the reaction between [Cr2(OH)2(nta)2]2¯, Fe2+, and a,a' bpy in the presence of isonicotinic acid was performed. Thus, a new complex with the composition [Fe(bpy)3][Cr2(mOH)(m-iNic)(nta)2]*9.5H2O, as a result of the interaction of the aqueous solutions, was obtained, and were characterized by IR spectroscopy, X-ray analysis and magnetochemistry. The new anion [Cr2(m-OH)(m-iNic)(nta)2]2¯ contains the rest of the iso-nicotinic acid, which serves as a bridging ligand, coordinated through the O and O' atoms, between two Cr(III) atoms of dimer.