A polar compound has a high chemical stability, high ability to align liquid crystal molecules and high solubility in a liquid crystal composition, and causes no decrease of liquid crystallinity of the liquid crystal composition, a liquid crystal composition contains the compound, and a liquid crystal display device includes the composition. The compound is represented by formula (1), the composition contains the compound, and the liquid crystal display device uses the composition. ##STR00001## In formula (1), R.sup.1 is alkyl having 3 to 15 carbons, alkenyl having 4 to 15 carbons or the like; a is an integer from 2 to 12; and R.sup.2 is a group represented by formula (1a), formula (1b) or formula (1c). ##STR00002## In the formulas, S.sup.1 and S.sup.2 are independently a single bond, alkylene having 1 to 10 carbons; S.sup.3 is >CH— or >N—; S.sup.4 is >C< or >Si<; and X.sup.1 is —OH, —NH.sub.2 or the like.

A liquid crystal composition and a display device are provided. The liquid crystal composition includes a compound having a structure represented by general formula (I) and a compound having a structure represented by general formula (II), ##STR00001## and L.sub.1, L.sub.2, L.sub.3 and L.sub.4 are independently selected from ##STR00002## Z.sub.1 is selected from a single bond or —C≡C—; R.sub.1, R.sub.2 and R.sub.3 are independently selected from alkyl, alkenyl, alkynyl, haloalkyl or OR.sub.4; and R.sub.4 is selected from alkyl, alkenyl, alkynyl or haloalkyl.

A liquid crystal composition and a display device are provided. The liquid crystal composition includes a compound having a structure represented by general formula (I) and a compound having a structure represented by general formula (II),

##STR00001##

and L.sub.11, L.sub.2, L.sub.3 and L.sub.4 are independently selected from

##STR00002##

Z.sub.1 is selected from a single bond or —C≡C—; R.sub.1, R.sub.2 and R.sub.3 are independently selected from alkyl, alkenyl, alkynyl, haloalkyl or OR.sub.4; and R.sub.4 is selected from alkyl, alkenyl, alkynyl or haloalkyl.

A liquid crystal composition having good photostability and thermostability. The liquid crystal composition comprises: 5-30% of one or more compounds of general formula I based on the total weight of the liquid crystal composition; 1-30% of one or more compounds of general formula II based on the total weight of the liquid crystal composition; 1-30% of one or more compounds of general formula III based on the total weight of the liquid crystal composition; 1-20% of one or more compounds of general formula IV-1 and/or general formula IV-2 based on the total weight of the liquid crystal composition; and 15-50% of one or more compounds of general formula V based on the total weight of the liquid crystal composition. A liquid crystal display element containing the liquid crystal composition is also provided.

##STR00001##