Quaterrylenebis(dicarboximide)s: near infrared absorbing and emitting dyes

New ladder-type chromophores, the quaterrylenebis (dicarboxdiimide)s 2, 18 and 23, have been synthesised which, despite their extended pi-system, exhibit good solubility in organic solvents and film forming properties when adequately substituted. These unprecedented dyes, which absorb and even emit light in the NIR window, are also characterized by oustanding chemical, thermal and photochemical stability with regard to their absorption range. The potential formation of J-aggregates in strongly acidic media has been investigated and has been ruled out by combined H-1 NMR and UV-VIS-NIR spectroscopy experiments. In addition, their photophysical and electrochemical characteristics have been explored and are discussed.