An ortho­rhom­bic polymorph of 5-[(4-methyl­phen­yl)diazen­yl]salicylaldehyde

The title compound, C14H12N2O2, is an ortho­rhom­bic polymorph of the previously reported monoclinic form [Bakir et al. (2005). Acta Cryst. E61, o1611–o1613]. The dihedral angle between the aromatic rings is 4.32 (13)°. The mol­ecular structures of the two polymorphs, including short intra­molecular O—H⋯O hydrogen bonds between the the hydr­oxy and keto groups, are quite similar but their crystal packings are distinct. Unlike the monoclinic form, in which centrosymmetrically related hydr­oxy and keto groups form {⋯H⋯O}2 synthons via weak O—H⋯O contacts, leading to dimeric aggregates, in the ortho­rhom­bic form, the hydrogen bonding between these groups leads to the formation of supra­molecular chains orientated along the a axis.