An optically active compound represented by formula (I):
wherein R¹ represents an alkyl group having from 6 to 18 carbon atoms or an alkoxy group having from 6 to 18 carbon atoms; A represents
represents a nitrogen-containing hetero-aromatic ring; n and m each represents 0 or 1; R² represents an alkyl group having from 1 to 12 carbon atoms; and C* is an asymmetric carbon atom. The compound of formula (I) exhibits excellent physicochemical stability, a low temperature range for the chiral smectic C phase when used either alone or in combination with other compounds, and a rapid response.
An optically active compound represented by formula (I): ##STR1## wherein R.sup.1 represents an alkyl group having from 6 to 18 carbon atoms or an alkoxy group having from 6 to 18 carbon atoms; A represents ##STR2## or ##STR3## wherein ring ##STR4## represents a nitrogen-containing hetero-aromatic ring; n and m each represents 0 or 1; R.sup.2 represents an alkyl group having from 1 to 12 carbon atoms; and C* is an asymmetric carbon atom. The compound of formula (I) exhibits excellent physicochemical stability, a low temperature range for the chiral smectic C phase when used either alone or in combination with other compounds, and a rapid response.