1,4-Dihydropyrrolo[3,2-]pyrrole modified with dibenzoxazepine: a highly efficient core for charge-transfer-based OLED emitters.

The present work is focused on designing novel heteroaromatic systems, formally a hybrid of dibenzo[,]oxazepines and 1,4-dihydropyrrolo[3,2-]pyrroles (DHPPs). Straightforward synthesis affords a family of rigid, centrosymmetric, π-expanded aromatic heterocycles amenable to facile post-functionalization. The rigidified molecular architecture is responsible for several key photophysical features including (1) the excellent blue colour purity (full width at half maximum parameter = 0.