2-{(<i>E</i>)-[(2<i>Z</i>)-(3-Chloro-1-methyl-2,2-dioxo-3,4-dihydro-1<i>H</i>-2,1-benzothiazin-4-ylidene)hydrazinylidene]methyl}phenol

In the title compound, C(16)H(14)ClN(3)O(3)S, the thia-zine ring adopts a sofa (half-chair) conformation, with an r.m.s. deviation from the mean plane of 0.23 Å. The S atom and S-bonded C atom exhibit the maximum deviations from the thia-zine mean plane [-0.3976 (12) and 0.3179 (14) Å, respectively]. The conformations around the double bonds in the R(2)C=N-N=CHR unit are Z and E. An intra-molecular O-H⋯N hydrogen bond with the hy-droxy group as donor generates an S(6) ring motif. In the crystal, pairs of weak C-H⋯O inter-actions connect the mol-ecules, forming inversion dimers.