A mesomorphic compound represented by the following formula (I):
wherein R1 and R2 respectively denote a linear or branched alkyl group having 1 - 18 carbon atoms capable of including one or two or more non-neighboring methylene groups which can be replaced with -O-, -S-,
-CH = CH-, -C≡C- or
wherein X denotes halogen; X1 and X2 respectively denote
Z, denotes
or -CH20-; A1 denotes a single bond,
and Y1 and Y2 respectively denote H, F, Cl, Br, -CH3 or -CF3 with the proviso that Y, and Y2 are not simultaneously H. The mesomorphic compound is effective for providing a ferroelectric liquid crystal composition showing an improved low-temperature operation characteristic and a decreased temperature-dependence of response speed.
A mesomorphic compound represented by the following formula (I): ##STR1## wherein R.sub.1 and R.sub.2 respectively denote a linear or branched alkyl group having 1-18 carbon atoms capable of including one or two or more non-neighboring methylene groups which can be replaced with ##STR2## wherein X denotes halogen; X.sub.1 and X.sub.2 respectively denote ##STR3## Z.sub.1 denotes ##STR4## A.sub.1 denotes a single bond, ##STR5## and Y.sub.1 and Y.sub.2 respectively denote H, F, Cl, Br, --CH.sub.3 or --CF.sub.3 with the proviso that Y.sub.1 and Y.sub.2 are not simultaneously H. The mesomorphic compound is effective for providing a ferroelectric liquid crystal composition showing an improved low-temperature operation characteristic and a decreased temperature-dependence of response speed.