Thermolysis of [M(SeCH2CH2CH2NMe2)2] (M = Zn, Cd, Hg), prepared by the reactions of sodium salt of 3-(N,N-dimethylamino)propaneselenolate with metal acetates, afforded metal selenides (MSe). The metal selenides were characterized by XRD, EDAX, SEM, AFM, and TEM techniques. Nanoparticles of HgSe were prepared by pyrolysis in a quartz boat, solvothermal, and sonochemical methods. EDAX showed 1:1 Hg/Se ratio, while XRD and SAED patterns confirmed the formation of cubic HgSe. These particles are spherical in nature with an average diameter of 15 nm (from TEM).