An optically active compound of the general formula (1) useful as a chiral
dopant and use thereof,
##STR1##
wherein each of m and n is independently an integer of 4 to 8, A is
--Ph--COO--Ph--, --Ph--Ph--COO--, --Cy--COO--Ph--, --Ph--OOC--Ph--COO--,
--Ph--OOC--Cy--COO--, --Ph--OOC--Np--COO-- or --Np--OOC-- in which --Ph--
is a 1,4-phenylene group, --Cy-- is a trans-1,4-cyclohexylene group and
--Np-- is a 2,6-naphtylene group, and C* is an asymmetric carbon atom.
Having a helical twisting power (HTP) of at least 9 and having a property
that the helical pitch induced decreases with an increase in temperature,
the optically active compound of the present invention has an excellent
value as a chiral dopant for a nematic liquid crystal.
