Homoleptic mercaptides of noble metals (i.e., Me(SR)(x), where R is a linear alkyl group, i.e., CnH2n+1) dissolved in polymer undergo a thermal degradation process at moderately low temperatures (180-250 degrees C), producing metal atoms that then give nanosized metal particles by clustering. As an example, the preparation of palladium, gold, and silver clusters dispersed in polystyrene has been described, but such chemical route is a very general approach and a variety of metal/polymer combinations can be equivalently obtained.