Planar, Fluorescent Push–Pull System That Comprises Benzofuran and Iminocoumarin Moieties

Previously unknown, vertically linked
heterocycles comprised of
benzofuran and iminocoumarin moieties have been synthesized directly
from 1,5-dibenzoyl­oxyanthra­quinone and aryl­aceto­nitriles
via double Knoevenagel condensation followed by formal HCN elimination.
The structural assembly of fully conjugated, electron-rich benzofuran
and electron-deficient iminocoumarin is responsible for the strongly
polarized nature of these heterocycles which translates into their
polarity-sensitive fluorescence.