Crystal structures of the sulfones of 2,3-diphenyl-2,3-di­hydro-4H-1,3-benzo­thia­zin-4-one and 2,3-diphenyl-2,3-di­hydro-4H-pyrido[3,2-e][1,3]thia­zin-4-one

The title sulfones, 2,3-diphenyl-2,3-di­hydro-4H-1,3-benzo­thia­zine-1,1,4-trione, C20H15NO3S, and 2,3-diphenyl-2,3-di­hydro-4H-pyrido[3,2-e][1,3]thia­zine-1,1,4-trione, C19H14N2O3S, crystallize in space group P21/n with two mol­ecules in each of the asymmetric units and have almost identical unit cells and extended structures. In both structures, the thia­zine rings exhibit a screw-boat pucker. The inter­molecular inter­actions observed are C—H⋯O-type hydrogen bonds and parallel partial π–π stacking between the fused aromatic rings (benzo- or pyrido-) of the core of the mol­ecules within each asymmetric unit, and also connecting to mol­ecules with translational periodicity in the a-axis direction in what can be described as columns (two per asymmetric unit) of stacked mol­ecules with alternating chirality. The pendant phenyl groups of both mol­ecules do not participate in aromatic ring inter­actions.