Patent ID: 8389741

Claim:
A difluoroboradiazaindacene dye of the formula (1) where R 1 =fluoro-substituted phenyl residue C 6 H m F n where n=1 to 5 and m+n=5; or fluoro-substituted naphthyl residue C 10 H m F n where n=1 to 9 and m+n=9; R 2 =CH 3 , C 2 H 5 , C 3 H 7 , or C 4 H 9 ; R 3 =alkyl, aryl, or vinyl aryl; R 4 , R 5 =H, F, or an R 4 and R 5 bridging residue CH═CH—CH═CH; R 6 , R 7 =H, F, or an R 6 and R 7 bridging residue CH═CH—CH═CH; and R 8 =alkyl or aryl.