We have examined the relative stabilities of a number of heterocyclic systems containing divalent sulfur by applying the conjugated circuit model. Comparison is made with earlier reported resonance energies of these compounds, obtained by employing the HMO and SCF π-MO models and appropriate reference structures, indicating a fair parallelism. The approach is then extended to numerous polycyclic sulfur-containing systems synthesized in the last decade and is used for discussing the relative stabilities of positional isomers producing the qualitative explanation for the differences amongst such isomers. Finally, we made predictions on yet unknown structures with divalent sulfur, extending the study to polycyclic systems involving fused rings other than benzene.