Metal oxide materials are one of the promising materials for low power consumption devices due to their unique size and dimensionality dependent physical and chemical properties. Low cost of production is also a key component in micro/nanoscale devices. Cupric oxide (CuO) nanostructures are of particular interest because of their interesting properties and promising applications in solar cells, bio and gas sensors, batteries, super capacitors, catalysis, photo detectors, energetic materials and removal of organic pollutants from waste water. An attempt has been made to synthesize randomly oriented rectangular shaped nanostructures of CuO, via hydrothermal synthesis at low temperature (~70 °C) on top of NiO porous structured film. The film was deposited using chemical bath deposition method at room temperature using ITO coated glass plate as a substrate. One can observe that the CuO growth on NiO/ITO substrate not only filled the porous structures of NiO but also formed the long rectangular shaped nanostructures which were randomly oriented on top of NiO surface. The CuO rectangular nanostructures have the dimensions in order of (6±2.0) μm x (2.0±0.5) μm. The randomly oriented rectangular structure can assist the charge transport in between the different semiconducting layers. These rectangular shaped nanostructures can also be used in nano-electronic devices, or as a p-type conducting wires in future electronic device applications. The present study is limited to the surface morphology studies of the nanostructured thin layers of NiO/CuO composite materials. Structural and absorption measurements of the CuO/NiO hetero junction have been studied using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), UV spectroscopy. The energy band gap of both layers NiO and CuO have been calculated using UV spectroscopy and discussed further. Therefore, the present rectangular structure of CuO could be helpful for the purpose of designing novel function nanostructures for efficient energy harvesting.