Molecular geometry, electronic structure, effect of the substitution and structure physical-chemical property relationship for 1,2- dithiole-3-thione derivatives, have been studied by molecular mechanics, PM3, Ab initio, DFT and QSAR method. In the present work, the calculated values, namely net charges, bond lengths, dipole moments, electron-affinities, heats of formation and QSAR properties, are report- ed and discussed in terms of the biological activity of 1,2-dithiole-3-thione derivatives. Keywords- 1,2-dithiole-3-thione, QSAR Properties, Structure, Ab intio, DFT