(2 Z )-2-Benzylidene-4-octadecyl-3,4-dihydro-2 H -1,4-benzothiazin-3-one

The octadecyl chain in the title compound, C 33 H 47 NOS, is in the `fully extended' conformation. A puckering analysis of the thiazine ring was performed. The molecules form micellar blocks in the crystal by intercalation of the extended octadecyl chains and association of the dihydro benzothiazine units through C—H...O hydrogen bonds. These blocks are associated through intercalation of the pendant phenyl groups which reside on the outer edges of each block.