A liquid crystal compound having a relatively low viscosity, a superior compatibility with other liquid crystalline compounds and suitable for preparing a liquid crystal device having a high response rate, and a superior liquid crystal composition containing the compound are provided, which compound is expressed by the formula ##STR1## wherein R.sup.1 is H, F, Cl, CN or 1-20C alkyl or alkenyl in which alkenyl one --CH.sub.2 -- group or two not adjacent --CH.sub.2 -- groups may be replaced by --O-- and in which alkenyl the position and number of the double bond may be optionally chosen; A.sup.1, A.sup.2 and A.sup.3 are ##STR2## the H atom(s) of which ##STR3## may be replaced by F, Cl or methyl; B.sup.1 and B.sup.2 are --CH.sub.2 CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 -- or single bond; n is 0 or 1; and m is 0 to 20.
提供了一种具有相对低粘度、与其他液晶化合物相容性优良且适用于制备具有高响应速率的液晶器件的液晶化合物和优良的液晶组合物,该化合物由以下式子表示:##STR1## 其中,R1为H、F、Cl、CN或1-20C烷基或烯基,其中烯基中的一个-
CH2-基团或两个不相邻的- -基团可以被-O-替换,且烯基中的双键位置和数量可以选择;A1、A2和A3为##STR2## 其中,其H原子可以被F、Cl或甲基替换;B1和B2为-- --、-- O--、--O --或单键;n为0或1;m为0至20。