1.1'-Bi-1H-imidazole. 2.2'-bis(chlorophenyl)-4.4'.5.5'-tetraphenyl-

1.1'-Bi-1H-imidazole. 2.2'-bis(chlorophenyl)-4.4'.5.5'-tetraphenyl- 5g : 1.1'-Bi-1H-imidazole. 2.2'-bis(chlorophenyl)-4.4'.5.5'-tetraphenyl- is a high-efficiency photoinitiator for UV-curable resins and coatings.