5'-Amino-1,3-dioxo-2',3'-di-hydro-7'H-spiro-[indane-2,7'-thieno[3,2-b]pyran]-6'-carbonitrile 1',1'-dioxide.

The title compound, C(16)H(10)N(2)O(5)S, was synthesized via the condesation of dihydro-thio-phen-3(2H)-one 1,1-dioxide, 1H-indene-1,2,3-trione and malononitrile in ethanol. The 2,3-dihydro-thio-phene 1,1-dioxide and pyran rings adopt envelope conformations. The mean planes through the planar part of the pyran ring and the benzene ring are nearly perpendicular, forming a dihedral angle of 88.40†(7)°. The crystal packing is stabilized by inter-molecular N-H⋯O and N-H⋯N hydrogen bonds with the sulfone O atom and the cyano N atom acting as acceptors.