Simultaneous growth of Magnesium Oxide (MgO) nanowires and nanocubes using chemical vapor deposition was reported in this research paper, which were grown without any substrate and catalyst. The literature survey reveals that, this type of preparation is first of its kind. The simultaneous growth of MgO nanowires and nanocubes are later deposited on an Over Head Projector (OHP) sheet. The prepared structure was characterized by X-ray diffraction, SEM and TEM analysis. XRD revealed that prepared MgO has cubic structure. The nanocubes and nanowires sizes range from few nanometer to hundreds of nanometers. HRTEM confirmed the prepared nanostructure is crystalline. Energy dispersive X-ray Analysis showed the elemental composition is indeed MgO. The study of FTIR gave the vibrational spectra of MgO nanostructures. Possible growth mechanism was discussed with supported schematic diagram. Above all, the prepared nanostructures were coated on over head projector (OHP) sheet and used as flexible gas sensor. The device was tested under Hydrogen gas for different concentration. Copyright © 2017 American Scientific Publishers All rights reserved.