The Aromatic Character of Diindeno[2,1- b :2',1'- h ]biphenylene.

The tropicity of the title system was studied using NICS(1.7) π,zz - XY -scans and current density analysis, showing a global diatropic loop and local dia- and paratropic loops. This aromaticity picture is very different from the one proposed based on NICS(1) and HOMA ( Org. Lett. 2021, 23, 8794-8798). It is predicted that 1 should be suitable for singlet fission applications. It is concluded that local aromatic indices should not be used for the full analysis of multiring conjugated systems.