title: 4-[(E)-(5-tert-Butyl-2-hydroxy-phen-yl)diazen-yl]benzoic acid benzene hemisolvate.
abstract: The title benzene hemisolvate, C(17)H(18)N(2)O(3)·0.5C(6)H(6), features an essentially planar (the r.m.s. deviation of the non-H atoms, excluding methyl-C, is 0.071 Å) diazo mol-ecule with an E conformation about the N=N bond, and a half-mol-ecule of benzene disposed about a centre of inversion. The dihedral angle formed between the benzene rings of the diazo mol-ecule is 7.69 (12)°. In the crystal, centrosymmetrically related dimers associate via the eight-membered carboxylic acid dimer synthon, {⋯HOC(=O)}(2), and these are connected into a supra-molecular chain along the b axis via C-H⋯O contacts.
authors.forename: Tushar S
authors.initials: TS
authors.lastname: Basu Baul
authors.forename: Anup
authors.initials: A
authors.lastname: Paul
authors.forename: Edward R T
authors.initials: ER
authors.lastname: Tiekink