B,N-doped PAHs from tridentate 'Defects' - a bottom-up convergent approach for π-extended systems.

A logical construction of monomeric subunits armed with the carbonyl functionality allowing post-synthetic reactivity leads to the convergent formation of π-extended defected units activated with BBr. The kinetic or thermodynamic control entraps either the pyrido[2,3-]quinoline or the 4,7-phenanthroline motifs doped with boron(III), which deeply modulates the optical properties.