Annulating thiazolium cations via a direct double C-H activation strategy: Rh-N,S-heterocyclic carbene is the key.

Herein we show how metal-N,S-heterocyclic carbene intermediates are conveniently generated and utilized for the first time to construct N,S doubly-doped cationic conjugated tricyclic organic molecules which exhibit tuneable emission. The chemistry proceeds via direct double C-H activation followed by an annulative π-extension pathway.