Polycyclic compound, liquid crystal material consisting of the polycyclic compound, liquid crystal composition comprising the liquid crystal material, and liquid crystal element

A polycyclic compound represented by the following formula (I):

• R.sup.1 --X.sup.1 --[A.sup.1 --X.sup.2 ]--[A.sup.2 --X.sup.3 ]--R.sup.2 (I)
• wherein R.sup.1 is an alkyl group of 6 to 16 carbon atoms or a halogenated alkyl group of 6 to 16 carbon atoms, each of which may have optical activity, and a part of --CH.sub.2 -- groups, --CHL-- groups or --CL.sub.2 -- groups (L is a halogen atom) constituting said alkyl or halogenated alkyl groups, which are not directly bonded to X.sup.1 and not adjacent to each other, may be replaced with --O-- group;
• X.sup.1 is --O-- group or a single bond;
• A.sup.1 is a group selected from the following group (a) and A.sup.2 is a group selected from the following group (b), or A.sup.1 is a group selected from the following group (b) and A.sup.2 is a group selected from the following group (a);
• group (a):
• a biphenylene group, a fluorine-substituted biphenylene group, a phenylene group, a fluorine-substituted phenylene group and ##STR129## group (b):
• ##STR130## wherein p is an integer of 1 to 7, q is an integer of 1 to 4, r is an integer of 0 to 3, Y is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group;
• X.sup.2 and X.sup.3 are each independently --COO--, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CH.dbd.CH--COO--, --C.tbd.C--COO--, --CH.sub.2 CH.sub.2 COO-- or a single bond;
• and
• R.sup.2 is an optically active group of 4 to 20 carbon atoms, which has at least one asymmetric carbon atom.