Higher Order Acenes and Fused Acenes with Near-infrared Absorption and Emission

Higher order acenes and fused acenes represent two outstanding classes of building blocks to achieve near-infrared absorbing and emitting materials. Appropriate chemical modification and functionalization will lead to significant improvements in solubility and stability, thus making their applications practically possible. This short review summarizes the recent developments of the two types of polycyclic aromatic compounds mentioned above based on their physical and optical properties including absorption, emission, quantum yield, solubility, and stability.