An Azulene‐Fused Tetracene Diimide with a Small HOMO–LUMO Gap

A newly prepared tetraazulene‐fused tetracene diimide (TA‐fused TDI) showed absorption in the near‐IR region owing to the effective extension of the π‐conjugated system as well as a large two‐photon absorption cross‐section (σ(2)=2140 GM) at 950 nm. Four reversible reduction processes and n‐type semiconductivity were also confirmed as attractive electronic properties of this compound. Banded together: A tetraazulene‐fused tetracene diimide (see figure), which was prepared by Suzuki–Miyaura cross‐coupling and oxidative cyclization, exhibited near‐IR absorption, strong two‐photon absorption, four reversible reduction processes, and n‐type semiconductivity.