| abstract |
A novel oxocarbon-based compound having no shoulder peak (or greatly reduced) in an absorption spectrum in a visible / near infrared region is provided. The oxocarbon compound of the present invention is characterized by being represented by the following formula (1) or (2). [In the formulas (1) and (2), R a1 to R a4 each independently represent a structural unit represented by the following formula (3). (In the formula (3), ring A is an unsaturated hydrocarbon ring of 4 to 9 atoms, X and Y are each independently a functional group, n is an integer of 0 to 6, and m or less A is a value obtained by subtracting 3 from the number of constituent atoms of A, and when n is 2 or more, a plurality of Ys may be the same or different from each other; ring B represents an aromatic hydrocarbon ring, aromatic heterocyclic ring, (*) Represents a bonding site of a 4-membered ring in formula (1) or a 5-membered ring in formula (2))] |