Patent ID: 7094910

Claim:
An infrared dye of formula 4 as set out hereunder: wherein X 1 and X 2 are individually selected from the group consisting of oxygen and sulfur; Z 1 and Z 2 are individually selected from CR 3 where R 3 is selected from the group R; Y is independently ═O or a tautomer thereof or dimethyl; Q 1 , Q 2 , Q 3 and Q 4 are individually selected from the group consisting of R 4 , a fused 6-membered aromatic ring optionally substituted with 1 to 4 substituents individually selected from R 5 , and fused polyaromatic rings optionally substituted with one or more substituents selected from R 6 wherein R 4 , R 5 and R 6 are individually selected from the group R; R is the group consisting of hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a halide atom, a hydroxy group, a substituted or unsubstituted amine group, a substituted or unsubstituted alkoxy group; and n is 1 or 2 or 3.