New ladder-type chromophores, the quaterrylenebis(dicarboxdiimide)s 2, 18 and 23, have been synthesised which, despite their extended p-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 1H NMR and UV-VIS-NIR spectroscopy experiments. In addition, their photophysical and electrochemical characteristics have been explored and are discussed. Results and discussionlenebis(dicarboximide)s, namely the terryleneimides 7,815 and Synthesis The synthetic pathway to quaterrylenebis(dicarboximide)s 2a,b †Chercheur Qualifie ´au Fonds National de le Recherche Scientifique, is illustrated in Scheme 1. The key building block for the synthesis Universite ´libre de Bruxelles, Chimie Macromole ´culaire, CP 206/1, of quaterrylenebis(dicarboximide)s is the N-substituted pery-Boulevard du Triomphe,