Magnesium (Mg) doped zinc oxide (ZnO) is synthesized by nitriding method at 300 °C. XRD studies shows that crystallite size at 300 °C is 27.3 nm. The secondary phase shows the disruption of the hexagonal structure of the ZnO. EDAX confirms the presence of Zn, Mg and O and hence the sample is pure. FTIR studies confirm the presence of ZnO and MgO. Optoelectronic studies are also conducted and it has been confirmed that due to the doping of Mg and also which is present in secondary phase, the PL spectra shows a broad red shift from 633 nm to 651 nm, which shows the significance of the secondary phases.