| abstract |
A novel co-crystal compound and a near-infrared ink as an anti-counterfeit ink using the same are provided. The present invention relates to a co-crystal compound containing a specific fluorane compound and a specific 4,4′-sulfonyldiphenol derivative. The fluorane compound is preferably 3-dibutylamino-6-methyl-7-anilinofluorane, and the preferred 4,4′-sulfonyldiphenol derivative is 3,3′-diallyl-4,4′-. Dihydroxydiphenyl sulfone. [Selection figure] None |