Design and Properties of Azaacene‐Fused Porphyrins: Extending π‐Systems for NIR‐II Absorption

A series of porphyrins featuring various azaacene moieties were designed with the aim to explore the structure-property relationships in extended azaacene systems. The introduction of azaacene groups significantly enhanced the solubility of these chromophores while directly influencing their electronic absorption and emission properties, enabling absorption at longer wavelengths. Protonation of the azaacene-fused porphyrins further extended their absorption into the NIR-II region. The π system extension provided by the new appended diamino aromatic groups were therefore investigated through electrochemical, photophysical, X-ray diffraction structural studies and complemented by theoretical calculations.