The asymmetric unit of the title compound, C22H21N3O2, consists of two independent mol-ecules (A and B) having differing conformations. The differences mainly concern the dihedral angles which the hy-droxy-phenyl and di-methyl-phenyl rings subtend to the central phenyl-ene ring, these being 30.16 (6) and 58.60 (6)° in mol-ecule A and 13.42 (7) and 60.31 (7)° in B. With the exception of the dimethyphenyl substituent, the conformations of the rest of each mol-ecule are largely determined by intra-molecular O-H⋯N and N-H⋯O hydrogen bonds. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into chains extending parallel to the a axis in which the types of mol-ecules alternate in an …A…B…A…B… fashion.
Keywords: crystal structure; hydrazide-hydrazone compounds; hydrogen bonding; non-steroidal anti-inflammatory drugs (NSAIDs) mefenamic acid (MA).