Answer. Azo compounds are characterized by being derivatives of diazine, wherein both hydrogens (HN=NH) are substituted with hydrocarbyl groups (PhN=NPh). They have the functional group diazenyl R-N=N-R’. They are vividly colorful and are thus used as dyes in multiple industries. Azo compounds can be Aryl azo or Alkyl azo. Aryl azo compounds are stable and crystalline. Azo benzene is used as the aromatic azo compound. The oxidation of hydrazine creates azo compounds (R-NH-NH-R).Alkyl azo compounds are less commonly used. For example, diethyl diazene is an alkyl azo compound. In it, a racial initiator is used for the preparation of polymers.