Diazonium salts are versatile intermediates for introducing substituents like -F, -Cl, -Br, -I, -CN, -OH, -NO₂ into the aromatic ring through electrophilic substitution reactions, enabling the synthesis of substituted aromatic compounds that may not be directly prepared by other methods.

Coupling reactions involve the reaction of benzene diazonium chloride with phenol or aniline, leading to the formation of azo products like p-hydroxyazobenzene or p-aminoazobenzene. These reactions are examples of electrophilic substitution.

Coupling reactions involving benzene diazonium chloride with phenol or aniline result in the formation of azo products, such as p-hydroxyazobenzene and p-aminoazobenzene, respectively. These compounds, with extended conjugate systems, are often colored and utilized as dyes.

When diazonium fluoroborate is heated with aqueous sodium nitrite in the presence of copper, the diazonium group is replaced by a -NO₂ group.

Hydrolysis of a diazonium salt occurs when the temperature of the solution rises to 283 K, leading to the formation of phenol.