We investigate the deposition temperature that govern evolution of the nanoparticle shape NiSe nanoparticle arrays. NiSe semiconductor nanostructure thin films have been synthesized through a simple chemical bath deposition approach. X-ray diffraction characterization suggested that the product consists of hexagonal phase pure NiSe. The samples were also characterized by absorbance spectra for energy band gap determination, scanning electron microscopy (SEM) and EDAX technique for elemental analysis. The results showed that the deposition temperature plays a crucial role in the process and show a ‘red shift’ of ‘1.5 eV’ in their optical band gap. In comparison to other similar works, our method is simple, low cost and can be easily controlled.