A material suitable for a guest-host liquid crystal device comprises a solution of a liquid crystal material and a pleochroic dye wherein the pleochroic dye comprises at least one anthraquinone compound free from water solubilizing and ionic substituents and having the formula: ##STR1## wherein P is OH or NH.sub.2 ; each group X.sup.A is independently selected from OH, NO.sub.2, SR and NZ.sub.1 Z.sub.2 provided that one group X.sup.A is SR and the other group X.sup.A is OH, NO.sub.2 or NZ.sub.1 Z.sub.2 is 1 or 2; each group Q.sub.1 is independently alkyl having from 1 to 20 carbon atoms; each group R is independently selected from alkyl having from 1 to 20 carbon atoms, aryl having up to 15 carbon atoms and cycloalkyl having from 4 to 8 carbon atoms.