[en] To study the active performance of TiO₂ nanoparticles of different architecture in photo-electronic devices, the optical bandgap and the energy levels are to be determined aptly. In this article the energy band gap and their HOMO: LUMO positions of two different types of TiO₂ nanoparticles labeled as S(1) and S(2), derived from hydrothermal method by using two capping reagents CTAB (cetyl-trimethyl-ammoniumbromide) and TOAB (tetra-octyl-ammoniumbromide) have been reported. The material characterization was performed through PXRD, TEM, FTIR, TGA, UV-vis spectroscopy and cyclic voltammetry. The optical band gap from UV-vis absorption spectra and the energy levels i.e. HOMO: LUMO, estimated from electrochemical method are in accordance (Table-I). The direct band gap energy was estimated by Tauc‟s method. The phase related spectra of TiO₂ is supported by JCPDS card No.:84-1286. The CV measurements have been performed by three-electrode configuration. The platinum wires were used as working and counter electrodes and Ag/AgCl is used as the reference electrode. Thus the conclusion can be drawn as the accumulation of energy levels are highly depends on the growth of molecules and nucleation that is mainly controlled by the chain length of the surfactant and the vapor pressure of the solvent. (author)