title: 4-{(E)-2-[4-(But-3-en-1-yl-oxy)phen-yl]diazen-1-yl}benzoic acid.
abstract: The title compound, C(17)H(16)N(2)O(3), has an E conformation about the azobenzene (-N=N-) linkage. The benzene rings are twisted slightly with respect to each other [6.79 (9)°], while the dihedral angle between the plane through the carb-oxy group and the attached benzene ring is 3.2 (2)°. In the crystal, mol-ecules are oriented with the carb-oxy groups head-to-head, forming O-H⋯O hydrogen-bonded inversion dimers. These dimers are connected by C-H⋯O hydrogen-bonds into layers lying parallel to the (013) plane.
authors.affiliation: University Malaysia Pahang, Faculty of Industrial Sciences and Technology, 26300 Gambang, Kuantan, Pahang,  Malaysia.
authors.forename: Md Lutfor
authors.initials: ML
authors.lastname: Rahman
authors.forename: Huey Chong
authors.initials: HC
authors.lastname: Kwong
authors.forename: Mashitah
authors.initials: M
authors.lastname: Mohd Yusoff
authors.forename: Gurumurthy
authors.initials: G
authors.lastname: Hegde
authors.forename: Mohamed Ibrahim
authors.initials: MI
authors.lastname: Mohamed Tahir
authors.forename: Mohamad Zaki Ab
authors.initials: MZ
authors.lastname: Rahman