They are commonly used in combination with azo groups to give a sub-family of azo dyes; sometimes referred to as azopyrazolones (tartrazine, orange B, mordant red 19, yellow 2G).
These compounds are frequently used in conjunction with azo groups to create a sub-family of azo dyes known as azopyrazolones. This includes tartrazine, orange B, mordant red 19, and yellow 2G.