34.2.4—About azo compounds

Azo compounds contain an –N=N– group connecting carbon-containing groups, commonly two aromatic rings. Their extended conjugation allows strong absorption in the visible region and often produces intense colours.

In syllabus chemistry, azo compounds are linked to diazonium salts and coupling reactions; the N=N unit is the identifying structural feature.

An azo dye can be represented as Ar–N=N–Ar′, where substituents on either ring tune colour and solubility.

The azo link is not an amide or an amine: it has two nitrogens joined by a nitrogen–nitrogen double bond.