2-{[2-(1-Methyl-2,2-dioxo-3,4-dihydro-1H-2λ⁶,1-benzothia- zin-4-yl-idene)hydrazin-1-yl-idene]methyl}phenol

In the title compound, C₁₆H₁₅N₃O ₃S, the dihedral angle between the aromatic rings is 8.18 (11)° and the C=N - N=C torsion angle is 178.59 (14)°. The conformation of the thia-zine ring is an envelope, with the S atom displaced by 0.8157 (18) Å from the mean plane of the other five atoms (r.m.s. deviation = 0.045 Å). An intramolecular O - H⋯N hydrogen bond closes an S(6) ring. In the crystal, weak C - H⋯O interactions link the molecules, with all three O atoms acting as acceptors.