Patent ID: 8586736

Claim:
A perimidine-based squarylium dye comprising a compound represented by Formula (1): wherein 95% by mole or more of the compound of Formula (1) is an isomer A, the isomer A being an isomer of a peak shown in the longest retention time among all peaks due to isomers obtained by analysis of the compound represented by Formula (1) by means of reversed-phase high-performance liquid chromatography; and the compound of Formula (1) satisfies the following formulae: ( A 845 /A MAX )≦0.059, ( A 750 /A MAX )≦0.21, ( A 410 /A MAX )≦0.043, and ( A 345 /A MAX )≦0.063, where A MAX represents an absorbance at a maximum absorption shown in the absorption wavelength in the range equal to or more than 802 nm and equal to or less than 808 nm, A 845 represents an absorbance of the absorption wavelength of 845 nm, A 750 represents an absorbance of the absorption wavelength of 750 nm, A 410 represents an absorbance of the absorption wavelength of 410 nm, and A 345 represents an absorbance of the absorption wavelength of 345 nm, in an absorption spectrum of a solution formed by dissolution of the compound in a mixed solvent comprising 80% by volume of n-hexane and 20% by volume of tetrahydrofuran.