Liquid crystal composition

A liquid crystal composition comprising host liquid crystal composition and guest pleochroic dye dissolved in the composition, wherein the pleochroic dye is at least one member represented by the following general formula:

• ##STR77## where W:
• the group represented by the formula ##STR78## R1 designating a straight chain alkyl group having 2 to 18 carbon atoms or the group ##STR79## and in R1 a methylene group not adjacent to the nitrogen atom may be substituted by oxygen atom or sulfur atom, and R2 designates a hydrogen atom, an alkyl or alkoxy group having 1 to 7 carbon atoms, or a cyclohexyl group, and
• B.sup.0, B.sup.1, B.sup.2, B.sup.3 :
• --N.dbd.N--, --N.dbd.CH--, --CH.dbd.N--, COO--, --OCO--, --COS--, --SCO--, --OCH.sub.2 --, --CH.sub.2 O--, --SCH.sub.2 --, --CH.sub.2 S--, --NHCO--, --CONH--, or --CH.sub.2 CH.sub.2 --, and
• Z.sup.1 to Z.sup.18 :
• Hydrogen atom, halogen atom, methyl group, hydroxyl group, methoxy group, or a cyano group;
• and Z.sup.1 and Z.sup.2, Z.sup.4 and Z.sup.5, Z.sup.7 and Z.sup.8, Z.sup.10 and Z.sup.11, Z.sup.13 and Z.sup.14, and Z.sup.16 and Z.sup.17 may be bonded together to form a naphthalene ring, and
• n.sub.0, n.sub.3, n.sub.5, n.sub.7 :
• zero or 1, and
• n.sub.1, n.sub.2, n.sub.4, n.sub.6 :
• zero, 1 or 2, with the proviso that n.sub.3 is 0 when n.sub.2 is 0, n.sub.5 is 0 when n.sub.4 is 0, and n.sub.7 is 0 when n.sub.6 is 0, and
• Y.sup.1 :
• when n.sub.0 is 0, Y.sup.1 is a hydrogen atom, a halogen atom, an alkyl or alkoxy group having 1 to 18 carbon atoms, cyclohexyl group, a bicyclooctyl group, a nitro group, an aryl group, or a group shown by the formula ##STR80## while when n.sup.0 is 1, Y.sup.1 is a cyclohexyl group, a bicyclooctyl group or an aryl group,
• whereby said pleochroic dye has a solubility in the host liquid crystal composition which is improved as compared with corresponding pleochroic dyes not containing the end group W of the general formula, without reduction of the order parameter of said pleochroic dye in the host liquid crystal composition.