Azo coupling is a chemical reaction that involves the formation of an azo compound, which contains a nitrogen-nitrogen double bond (–N=N–). This process typically occurs between a diazonium salt and an activated aromatic compound, such as an aromatic amine or phenol. The reaction is significant in organic chemistry and is widely used in dye manufacturing, particularly for creating vibrant colors in textiles. In azo coupling, the diazonium salt acts as an electrophile, while the aromatic compound serves as a nucleophile. The reaction results in the substitution of a hydrogen atom on the aromatic ring with the azo group, leading to the formation of azo dyes. These dyes are known for their stability and bright colors, making them valuable in various applications, including textiles and printing inks.