Two hetero-bimetallic precursors, [Co(en)(3)](2)[Ni(edta)](3) and [Ni(en)(3)][Co(edta)](2) (en = ethylenediamine and edta(4-) = ethylenediaminetetraacetate anion), were synthesized in an aqueous solution. For the first time, this type of hetero-bimetallic precursors was used for the preparation of NiCo2O4 (nickel cobaltite) nanospinels by calcination method. The results clearly showed the effect of different precursors on the final nanoparticles. The actual yield for the preparation of the nanospinels from [Ni(en)(3)][Co(edta)](2) precursor was greater than the yield for [Co(en)(3)](2)[Ni(edta)](3) precursor. The nanospinels were characterized using different techniques such as FT-IR, UV-Vis, zeta potential measurement, X-ray diffraction analysis (XRD), field-emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett Teller (BET) surface area measurement. Also, the catalytic activity of NiCo2O4 nanospinels was investigated for the oxidation of Rhodamine B to innocuous compounds at room temperature in water. The oxidation reaction was carried out in a batch reactor at ambient temperature and pressure with different reaction parameters such as reaction time, dye concentration, and catalyst loading. The cationic dye Rhodamine B ([C28H31N2O3]Cl-+(-)) was almost completely oxidized in the optimized reaction conditions. In addition, the catalysts could be recovered and reused successfully several times. (C) 2015 Elsevier B.V. All rights reserved.