Highly Emissive Far Red/Near-IR Fluorophores Based on Borylated Fluorene-Benzothiadiazole Donor-Acceptor Materials

Stille, Suzuki–Miyaura and Negishi cross‐coupling reactions of bromine‐functionalised borylated precursors enable the facile, high yielding, synthesis of borylated donor–acceptor materials that contain electron‐rich aromatic units and/or extended effective conjugation lengths. These materials have large Stokes shifts, low LUMO energies, small band‐gaps and significant fluorescence emission >700 nm in solution and when dispersed in a host polymer. The perfect couple: Cross‐coupling enables the high yielding synthesis of borylated donor–acceptor materials that contain electron‐rich aromatics units and/or extended effective conjugation lengths. These materials have large Stokes shifts, low LUMO energies, small band‐gaps and significant fluorescence emission >700 nm in solution and in the solid state.