Manganese sulfide (MnS) is a wide band gap material which has the potential use in short wavelength optoelectronic devices, photo-catalysis, solar cells etc. To alter the various properties of MnS nanomaterial, it was decided to add magnesium (Mg) as the dopant. Mg-doped MnS nanomaterial was synthesized by microwave-assisted solution method. From XRD and HRTEM studies, the crystallite size of the sample was estimated. Optical characterization of the sample was done by recording the UV-visible-NIR spectrum. The luminescent properties of Mg-doped MnS nanomaterial was analysed. The functional groups of the sample was found by FTIR studies and thermal stability was checked by TG/DTA studies. Also, Mg-doped MnS nanomaterial was characterized by SEM, EDAX and SAED studies.