The　conformation,　aromaticity　and　gas-phase　acidity　(free　energy　of　deprotonation,　Delta　G(-))　of　1,　2-dithiosquaric　acid　(3,　4　-dihydroxy-3-cyclubutene-1,　2-dithione)　were　calculated　at　the　SCF　and　MP2　and　B3LYP　levels　using　6-311G(d,　p)　and　6-311+G(d,　p)　basis　sets.　The　global　minimum　found　on　the　potential　energy　surface　of　1,　2-dithiosquaric　acid　presents　a　planar　conformation.　The　ZZ　isomer　was　found　to　be　the　most　stable　one　of　the　three　planar　conformers.　The　aromatic　stabilization　energy　(E-AS)　and　magnetic　susceptibility　exaltation　(Lambda)　were　also　computed　by　using　the　homodesmotic　reaction　and　RHF-CSGT　(Continue　set　of　Gauge　Transformations)　(IGAIM,　a　slight　variation　on　CSGT)　and　B3LYP-CSGT(IGIAM)　methods　at　the　6-311+G(d,　p)　level.　The　calculated　EAS　and　were　more　negative　values,　indicating　that　1,　2-dithiosqaric　acid　is　aromatic.　Thus　the　titled　compound　fulfilled　the　geometrical,　energetic　and　magnetic　criteria　of　aromaticity.　The　most　reliable　theoretical　gas-phase　acidity　are　Delta　G(298.1)(-)　=　1278.2　kJ.mol(-1)　and　Delta　G(298.1)(-)　=　1648.5　kJ.mol(-1).