Photostable NIR‐II Pigments from Extended Rylenecarboximides

A series of near‐infrared (NIR) organic absorbers, named FNs and FPs, have been obtained with absorption maxima from 870 nm to 1100 nm and thus falling into the attractive second near‐infrared region (NIR‐II). The synthesis of their extended aromatic cores utilized an initial aryl‐amination between 4‐aminonaphthalene‐1,8‐dicarboximide (NMI‐NH(2) ) or 9‐aminoperylene‐3,4‐dicarboximide (PMI‐NH(2) ) with chloro‐substituted 9,10‐anthraquinones followed by a novel base‐induced cyclodehydrogenation. A NIR‐II pigment, compound FPP, was obtained through de‐alkylation of a soluble precursor. The synthesis of this photostable pigment is high‐yielding and avoids column chromatographic purification which is important for many applications.