NiO/CuO/ZnO combined semiconductor metal oxide structures based ternary nanocomposites were synthesized in 2:1:1,1:2:1 and 1:1:2 molar ratios using a simple and combined co-precipitation - hydrothermal method without utilizing any fuels, capping agents or surfactants. The structural, bonding, band gaps and morphological behaviour of the synthesized ternary nanocomposites were investigated using x-ray diffraction, Fourier transform infrared spectroscopy, UV-Diffuse reflectance spectroscopy and atomic force microscopic measurements. The dielectric properties recorded for these combined semiconductor metal oxide structures are valid with Maxwell-Wagner (M-W) model which is based on the dielectric nature in conducting grains layered with poorly conducting grain boundaries. The higher values of dielectric constant were observed for the ternary nanocomposite ratio 1:2:1 and the reduction in the values of dielectric constant of other ternary nanocomposite ratios (1:1:2 and 2:1:1) at lower frequencies is due to the fact the grain boundaries are preferably occupied by more Cu2+ ions than N i 2 + and Zn2+ ions. This kind of attempt in investigating the physical insights of combined semiconductor metal oxide structures is needed for the development of novel semiconducting devices. © 2018IOP Publishing Ltd.