Photoinitiator tmbi (2,3,3-trimethyl-4,5-benzo-3h-indole), with molecular formula of c15h15n and molecular weight of 209.2863. It is mainly used as a dye and pharmaceutical intermediate. It is a very important basic heterocyclic intermediate for the synthesis of benzoindocyanine dyes. It is also a key intermediate for the synthesis of a variety of phototropic dyes. It is widely used in cyanine dyes, electroluminescent materials, and pharmaceutical intermediates.