Dichroic liquid crystal compositions containing anthraquinone-based dyes

A method of improving the color of dichroic dyes for use in liquid crystal displays comprising adding to a host liquid crystal material, a dye composition having a mixture of dichroic dyes of various colors in proper proportion to obtain a material which absorbs radiation in at least part of the spectral range of about 400-700 nm wherein at least one of the dichroic dyes of various colors is an anthraquinone-based dye having at least one lateral 5-membered, N-substituted dicarboxyimide ring joined to the outermost carbon atoms having the formula ##STR31## where R is a member selected from the group consisting of an alkoxyalkyl radical having from 1 to 4 carbon atoms in the alkyl and oxyalkyl segment and a straight chain or branched chain alkyl radical having from 1 to about 10 carbon atoms.

Liquid crystal mixture intended for electro-optical displays having no polarizers, consisting of:

• a nematic liquid crystal as the host phase,
• an optically acitve additive to give the host phase a cholesteric structure, and
• at least one pleochroic anthraquinone dye as the guest phase dissolved in the host phase, said anthraquinone dye having the formula ##STR32## wherein R.sup.5 is a member selected from an alkyloxyalkyl radical having from 1-4 carbon atoms in the alkyl and the oxyalkyl segment and an alkyl radical having from 1-10 carbon atoms.