Liquid crystalline mixtures containing compounds of the formula ##STR1## wherein n stands for the number 0 or 1; X.sup.1 and X.sup.2 denote single covalent bonds or one of the symbols X.sup.1 and X.sup.2 also denotes --COO--, --OOC-- or --CH.sub.2 CH.sub.2 --; the rings A.sup.1, A.sup.2 and A.sup.3 represent 1,4-phenylene, 2-fluoro-1,4-phenylene or trans-1,4-cyclohexylene or one of these rings also represents a 2,5-disubstituted pyrimidine ring or a trans-2,5-disubstituted m-dioxane ring; R.sup.1 signifies 4-alkenyl or on a cyclohexyl ring also 2Z-alkenyl; and R.sup.2 denotes alkyl, alkoxy, --CN or --NCS,as well as the manufacture of these compounds and the use for electro-optical purposes are described.