These are named by adding the word diazonium to the name of parent aromatic compound followed by the name of anion. For example, Benzene dizonium chloride.

Di nitrogen in the diazonium group develops charges due to bonded more electronegative chlorine. The developed charges are responsible for participating in specific reactions like Coupling reaction, Sandmeyer reaction, etc.

Benzene diazonium chloride reacts with phenol at para position to form p-hydroxy azobenzene. This type of electrophilic substitution is known as coupling reaction. The products are colored compounds that are used as dye in paint and textile industries.

It is used to convert an aryl diazonium salt to aryl halide using copper(I) halide as catalyst.

It is an alternate reaction for the Sandmeyer reaction. This is carried out with halogen acid in presence of copper powder.