Simple and effective synthetic pathways are described to prepare compounds R2P(X)C(S)SCH(Me)Ph with the P atom either in the oxidation state V [R/X = t-Bu/O (6), Ph/S, (7), t-Bu/S (8), t-Bu/Se (9)] or III [R/X = Ph/BH3 (4), t-Bu/BH3 (5), t-Bu/lone pair (10)]. Compound 9 is the first example of carbodithioate ester with a P=Se group and for the first time a phosphinocarboditioate with a free phosphine function (compound 10) is described. Stabilization of the latter crucially depends on the steric protection by the t-Bu groups, since an analogous derivative with R = Ph is observable but too unstable for isolation. Compound 10 can be reversibly protonated to yield the [t-Bu2PHC(S)SCH(Me)Ph] + cation (10-H +), which was isolated as a BF4-salt. A few interconversion processes resulting in the facile addition/removal or exchange of the X group in this family of compounds are also described. The phosphorus atom oxidation state and the nature of electron-withdrawing group have a significant impact on the spectral properties.