Amidodithiophosphonates were synthesised by the reaction of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide and amines such as (−)-cis–myrtanylamine amine, (R)-(+)–1–phenylethyl amine, (S)-(−)–1–phenylethyl amine in benzene. The compounds 1–3 were characterized by elemental analyses and spectroscopically (1H-, 13C, 31P NMR). In addition, the molecular geometry, vibrational frequencies, chemical shifts, electronic transition energies and thermodynamic parameters for the compound 1 were calculated by using the density functional method employing B3LYP level with different basis sets, including 6–31++G(d,p) and 6–311++G(d,p). The large HOMO-LUMO band gaps (5.08 eV and 5.06 eV, respectively) for the molecule explain the kinetic stability. The computed results are very close to the obtained experimental results with spectroscopic techniques.