Abstract: Dioxane derivatives for use as components in liquid crystal devices (LCDs) of general formula (A), wherein X is CH or B; R.sup.1, R.sup.2 are each A.sup.1, OA.sup.1, OCOA.sup.2, or COOA.sup.2 ; A.sup.1 is a straight or branched chain alkyl group containing from 1 to 20 carbon atoms and may be substituted with one or more F or CN. A.sup.2 is a straight or branched chain alkyl group containing from 1 to 20 carbon atoms and may be substituted with one or more F or CN and if straight may be unsubstituted. Y.sup.1, Y.sup.2, Y.sup.3 may each be (CH.sub.2).sub.p, (CH.sub.2).sub.p COO or OCO(CH.sub.2).sub.p ; p is from 0 to 10, n is 0 or 1, m is 0 or 1, either or both of Z.sub.1 and Z.sub.2 are F and, when not F, are H; Y.sup.4 is a covalent bond or, when n is 0, may be (a) LCDs, containing the devices exhibit very fast switching speed, bi-stable characteristics, enhanced greyscale and storage capabilities and a wide viewing angle.