In the title compound, C(19)H(13)N(3)O(3)S·0.5H(2)O, both organic mol-ecules (A and B) exist in E configurations with respect to the acyclic C=N bond and have similar overall conformations. In mol-ecule A, the essentially planar thia-zole ring [maximum deviation = 0.010 (2) Å] is inclined at inter-planar angles of 11.44 (10) and 32.50 (12)°, with the 2H-chromene ring system and the benzene ring, respectively. The equivalent values for mol-ecule B are 0.002 (2) Å, 7.71 (9) and 12.51 (12)°. In the crystal structure, neighbouring mol-ecules are inter-connected into infinite layers lying parallel to (010) by O-H⋯O, O-H⋯N, N-H⋯O and C-H⋯O hydrogen bonds. Further stabilization of the crystal structure is provided by weak inter-molecular C-H⋯π and π-π [centroid-centroid distance = 3.6380 (19) Å] inter-actions.