Intramolecular Direct Arylation Enables Access to Diverse Photophysical Properties for π-Expanded 1,4-Dihydropyrrolo[3,2-b]pyrroles

Dyes incorporating 1,4-dihydropyrrolo[3,2-b]pyrrole (DHPP) units are attractive platforms for organic optoelectronics because of their tunable electronic structures and intense fluorescence. Herein, we report a modular synthetic route to a diverse family of π-expanded DHPPs. The approach relies on double intramolecular direct arylation. This strategy provides efficient access to structurally complex dyes, including helically twisted and highly fused π-systems containing up to 20 conjugated aromatic rings and unique combination of optical properties. Several of the obtained dyes display pronounced solvatochromism, red emission, and circularly polarized luminescence (CPL). In particular, chiral resolution of a helicene-type derivative enabled detailed chiroptical studies and revealed configurationally stable enantiomers with good luminescence dissymmetry factor. A combination of experimental and computational analyses provided insight into the structure–property relationships governing their photophysical behavior, with particular emphasis on molecular symmetry and the substituent-dependent influence of nitro groups.