The invention includes compounds represented by Formula (1): ##STR00001## wherein R.sup.1 is an alkyl having 1 to 20 carbon atoms; A.sup.1 and A.sup.2 are a 1,4-cyclohexylene or 1,4-phenylene; X is a single bond, --C.ident.C--, --COO--, --OCO--, --CH.dbd.CH--COO-- or --OCO--CH.dbd.CH--; P is an alkylene having 1 to 20 carbon atoms; and p and q are 0, 1 or 2.