The magnesium oxide (MgO) nanoparticles were synthesised by solution combustion method. XRD results confirm the nanophase (crystallite size ∼30 nm) of a prepared sample with cubic structure. Mechanical stability assessments indicated excellent elastic moduli, highlighting the brittle nature of a material. Scanning Electron Microscopy (SEM) revealed the agglomerated and porous morphology of the MgO nanoparticles. UV–Visible characterization reveals an absorption peak at 295 nm, corresponding to an optical band gap of 3.6 eV. Photoluminescence spectroscopy identifies emission peaks at 406 nm, 436 nm, and 450 nm attributed to various structural defects. The frequency and temperature dependence on AC electrical properties were investigated at varying temperature (27oC–250oC) and frequency (50 Hz-5 MHz). The electrical modulus and Cole-Cole plots reveal relaxational behaviour and changes in the material's stiffness with temperature. From the obtained results it is evident that the synthesised MgO nanoparticles are suitable for electronic device applications. •Synthesis of MgO nanoparticles via solution combustion method yielding cubic crystal structure.•Structural and elastic analysis indicates anisotropic elastic properties and ductile nature.•UV–Vis spectroscopy identifies a significant absorption peak at 295 nm, unveiling an optical bandgap of 3.6 eV.•Dielectric analysis at different temperatures reveals conventional behavior with temperature and frequency variations.•AC conductivity analysis reveals Jonscher's power law behavior, showcasing frequency-dependent conductivity.