A novel method for the synthesis of a wide range of metal sulfides and selenides is described. Polysulfide solutions formed by the dissolution of sulfur in hydrazine monohydrate have been shown to contain the hexasulfide and tetrasulfide anions. The action of these solutions, or their selenium analogues, with a range of transition and main group metal salt solutions yields a precipitate, which after firing at an elevated temperature, forms a crystalline metal sulfide or selenide. This method of preparing metal chalcogenides has been extended to some group II-VI phosphors with promising luminescent properties.