Benzo-2,1,3-thiadiazole-based, highly dichroic fluorescent dyes for fluorescent host-guest liquid crystal displays

The highly dichroic fluorescent dyes 4,7-bis(p-alkoxyphenyl)-, 4,7-bis(p-alkoxymethylphenyl)-, and 4,7-bis(p-alkoxycarbonylphenyl)2,1,3-benzothiadiazoles have been synthesized and their dichroic properties evaluated. A solution of the former dye dispersed in the commercial liquid crystalline MLC-2039 host phase showed a dichroic ratio value for fluorescence up to 9.1.