title: 5H-Thio-chromeno[2,3-b]pyridine-5,10,10-trione.
abstract: The asymmetric unit of the title compound, C(12)H(7)NO(3)S, contains two independent mol-ecules with different geometric-al configurations. The dihedral angles between the benzene and pyridine rings in the two mol-ecules are 3.7 (2) and 5.40 (19)°. The central heterocyclic fused rings have different puckering parameters [Q = 0.122 (3) Å, θ = 100.4 (13), ϕ = 185.3 (19)° in one mol-ecule, 0.101 (3) Å, 101.4 (3) and 2 (2)° in the other]. The SO(2) group is oriented at dihedral angles of 81.06 (14) and 82.58 (15)° with the benzene and pyridine rings, respectively, in one mol-ecule [87.21 (14) and 87.66 (14)° in the second]. In the crystal, the mol-ecules are linked into zigzag polymeric chains along the b axis by inter-molecular C-H⋯O hydrogen bonding. π-π inter-actions with centroid-centroid distances in the range 3.825 (3)-4.153 (3) Å stabilize the structure. S-O⋯π and C-O⋯π inter-actions are also observed.
authors.forename: Muhammad Naeem
authors.initials: MN
authors.lastname: Khan
authors.forename: M Nawaz
authors.initials: MN
authors.lastname: Tahir
authors.forename: Misbahul Ain
authors.initials: MA
authors.lastname: Khan
authors.forename: Salma
authors.initials: S
authors.lastname: Rehman
authors.forename: Abdul Qayyum
authors.initials: AQ
authors.lastname: Ather