Properties of nanoscale materials are very interesting and these are either comparable to or superior to those of bulk. These materials are interesting due to their exciting size dependent optical, electronic, magnetic, thermal, mechanical and chemical properties. Different mole ratios of nanostructured mixed metal oxides of LaCo x Fe 1-x O 3-δ (x = 0 to 1) were prepared by the sol–gel method by varying the mole ratios of iron and cobalt substrates. The compounds were sintered for 700°C in the tubular furnace for 8 h. The purity of the compounds was analyzed by TG-DTA. The compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) studies were employed to study the structural phases, vibrational frequencies, surface morphology of the highest humidity sensing compounds.