The opening of the P2S2 tetraatomic ring of Lawesson’s reagent (4) has proved versatile in synthesizing phosphono‐ and amidophosphono‐dithioato mononuclear complexes [p‐CH3OPh(X)PS2]2M [X = CH3O, iPrNH; M = NiII, PdII, PtII]. A one‐step reaction of 4 with the appropriate metal salt in CH3OH, or in the presence of a stoichiometric amount of iPrNH2 in CHCl3, is used in the direct synthesis of the NiII and PdII complexes, but does not work in the PtII complexes. Alternatively, these syntheses can be carried out: i) by preparation and isolation of O‐methyl(4‐methoxyphenyl)phosphonodithioate (6) salts or isopropylamido(4‐methoxyphenyl)‐ phosphonodithioate (7) salts by treating 4 with CH3O− in CH3OH or with iPrNH2, respectively; ii) by reaction of 6 or 7 with MCl2 or K2MCl4 [M = NiII, PdII, PtII] to give trans‐bis[O‐methyl(4‐methoxyphenyl)phosphonodithioato]M and trans‐bis[isopropylamido(4‐methoxyphenyl)phosphonodithioato]M complexes. Following these routes, trans‐bis[O‐methyl(4‐methoxyphenyl)phosphonodithioato]M [M = Ni (8a), Pd (8b), and Pt (8c)] and trans‐bis[isopropylamido(4‐methoxyphenyl)phosphonodithioato]M [M = Ni (9a), Pd (9b), and Pt (9c)] complexes have been synthesized and fully characterized by FAB mass, FT‐IR, FT‐Raman, UV/Vis, and CP‐MAS 31P‐NMR spectroscopy; the crystal structures of 7, 8b, 8c, and 9a are also reported.