The present invention relates to a negative dielectric anisotropic liquid crystal composition, a liquid crystal display element, and a liquid crystal display. The negative dielectric anisotropic liquid crystal composition of the present invention comprises a first component composed of one or more compounds represented by formula I and a second component composed of one or more polymerizable compounds: The negative dielectric anisotropic liquid crystal composition disclosed by the present invention has a low rotary viscosity, a fast response speed and a good stability, and is very suitable for manufacturing liquid crystal display elements, particularly suitable for PS (polymer-stabilized) or PSA (polymer-stabilized alignment)-type liquid crystal displays.

##STR00001##

Liquid crystal compound satisfying at least one of physical properties such as high stability to heat or light, high maximum temperature, high clearing point, low minimum temperature of liquid crystal phase, small viscosity, suitable optical-anisotropy, large negative dielectric-anisotropy, suitable elastic constant and good compatibility with other liquid crystal compounds; liquid crystal composition containing the compound; and liquid crystal display device including the composition. Compound represented by formula (1), wherein R.sup.1 is alkyl having 1 to 15 carbons; R.sup.2 is alkyl having branched-chain and 3 to 15 carbons; A.sup.1, A.sup.2 are independently 1,2-cyclopropylene; Z.sup.1, Z.sup.2 are independently single bond or alkylene having 1 to 15 carbons; L.sup.1, L.sup.2 are fluorine, chlorine, OCF.sub.3 or OCH.sub.2F; X.sup.1, X.sup.2 are oxygen or sulfur; and a is 0 or 1, b is 0 or 1, and sum of a and b is 0, 1 or 2.

##STR00001##

The present invention discloses a compound of which a structural formula thereof is represented as the following formula

The compound disclosed by the present invention can be used as a liquid crystal compound and overcomes the problem that solubility of the traditional dibenzothiophene-class liquid crystals is poor, and thus can be better applied to the liquid crystal material field. The present invention further discloses a liquid crystal medium containing the compound and an application thereof.

##STR00001##

A liquid crystal display including a first substrate, a second substrate disposed opposite the first substrate, and a liquid crystal layer disposed between the first substrate and the second substrate. The liquid crystal layer includes a liquid crystal composition. The liquid crystal composition includes at least one of liquid crystal compounds including a cyclopentadienyl group.

The invention relates to novel compositions comprising at least two anisotropic compounds of formula ##STR00001##
as well as to liquid crystalline networks, films and electro-optical devices comprising the compositions.

A liquid crystal display includes a first substrate, a second substrate opposing the first substrate, an electrode portion provided on at least one of the first and second substrates, and a liquid crystal layer provided between the first substrate and the second substrate and including a liquid crystal composition. The liquid crystal composition includes a liquid crystal compound including a cyclohexenylene group, and provides the liquid crystal display with low rotary viscosity and high voltage holding ratio.

A liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy and large dielectric anisotropy, or having a suitable balance regarding at least two of the characteristics. The liquid crystal composition contains a quencher as a first additive, and may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having a polymerizable group as a second additive.

A liquid crystal composition satisfying at least one of characteristics such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy and large dielectric anisotropy, or having a suitable balance regarding at least two of the characteristics. The liquid crystal composition contains a quencher as a first additive, and may contain a specific compound having large negative dielectric anisotropy as a first component, a specific compound having high maximum temperature or small viscosity as a second component, or a specific compound having a polymerizable group as a second additive.

An object of the present invention is to provide a liquid-crystal display element using a liquid-crystal composition having negative dielectric anisotropy, capable of realizing excellent display characteristics by being used in a liquid-crystal display element provided with a photo-alignment film, without deteriorating various characteristics as a liquid-crystal display element such as dielectric anisotropy, viscosity, a nematic phase upper limit temperature, nematic phase stability at low temperatures, and 1, and burn-in characteristics of a display element. A liquid-crystal display element using a liquid-crystal composition containing at least one compound selected from the group consisting of compounds represented by the following General Formula (I) is provided. ##STR00001##

The present invention relates to polymerizable compounds, to processes and intermediates for the preparation thereof, and to the use thereof for optical, electro-optical and electronic purposes, in particular in liquid-crystal (LC) media and LC displays, especially in LC displays of the PS (polymer sustained) or PSA (polymer sustained alignment) type.