偶氮苯是最简单的芳香偶氮化合物，众多偶氮染料的母体结构。含有两个苯基分别与偶氮基–N=N–两端相连的结构。

沃勒合成尿素开创有机合成化学后第六年，Eilhard Mitscherlich 便报道了偶氮苯的合成。他用硝基苯与苛性钾反应，得到一个红色固体。他将该物质命名为“偶氮苯”（Azobenzol）。这比珀金合成苯胺紫要早22年。

很长时间内偶氮苯的组成一直不明。Mitscherlich 认为其化学式为 C₁₂ H₅ N。而有人通过蒸气密度实验，得出 C₂₄ H₁₀ N₂ 的化学式。 1860年，正确的化学式才由 P. Hofmann 提出。 1866年，凯库勒提出了正确的偶氮苯的结构式。

Azobenzene is a chemical compound composed of two phenyl rings linked by a N=N double bond. It is the simplest example of an aryl azo compound. The term 'azobenzene' or simply 'azo' is often used to refer to a wide class of molecules that share the core azobenzene structure, with different chemical functional groups extending from the phenyl rings. These azo compounds are considered as derivatives of diazene (diimide), and are sometimes referred to as 'diazenes'. The diazenes absorb light strongly and are used as dyes in a variety of industries.