NEW MATERIAL: The compound of the formula [D1 and D2 are independently a (substituted) aryl or a (substituted) heteroaryl].

USE: The coloring agent suitable to pigments, dispersed dyes or fat dyes for coloring natural materials and synthetic materials, such as PS, PE, PP, PVC, polyacryl compounds, polyesters, rubbers, casein resins, silicone resins yellow to red.

PROCESS: At least one diazotizable aromatic amine of a formula D-NH2 (D is D1) such as (substituted) aniline is diazotized, and then the diazotized compound is subjected to a coupling reaction in aqueous medium, under the presence of a nonionic, an anionic or a cationic surfactant a substance in necessary cases, by using a coupling agent of 1,5-diazabicyclo[3,3,0]octane-2,4,6,8-tetrone in an amount of 0.5 mole per 1 mole of the total diazonium salt to be reacted.