4,6-difluorodibenzofuran derivatives of the formula I

##STR00001##

the preparation thereof, the use thereof as components in liquid-crystalline media and electro-optical display elements which contain the liquid-crystalline media.

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I,

##STR00001##

in which
R.sup.1, R.sup.1*, Z.sup.1, Z.sup.2 and L.sup.1-3 have the meanings defined herein,
and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, PS-IPS or IPS effect.

Provided are a reactive mesogen that may improve display quality of a liquid crystal display, and a liquid crystal composition including the same. The reactive mesogen is represented by the following Formula:

##STR00001## where A.sub.1, A.sub.2, and A.sub.3 are each independently a substituted or unsubstituted divalent hydrocarbon ring, or a substituted or unsubstituted divalent heterocycle, L.sub.1 and L.sub.2 are each independently a direct linkage, O, S, CO, COO, OCOO, O(CH.sub.2).sub.k1, S(CH.sub.2).sub.k1, O(CF.sub.2).sub.k1, S(CF.sub.2).sub.k1, (CH.sub.2).sub.k1, CF.sub.2CH.sub.2, (CF.sub.2).sub.k1, CHCH, CFCF, CC, CHCHCOO, or (CH.sub.2).sub.k1COO(CH.sub.2).sub.k2O, Z.sub.1 and Z.sub.2 are each independently a direct linkage, O, S, CO, COO, OCOO, O(CH.sub.2).sub.m1, S(CH.sub.2).sub.m1, O(CF.sub.2).sub.m1, S(CF.sub.2).sub.m1, (CH.sub.2).sub.m1, CF.sub.2CH.sub.2, (CF.sub.2).sub.m1, CHCH, CFCF, CC, CHCHCOO, (CH.sub.2).sub.m1COO, (CH.sub.2).sub.m1COO(CH.sub.2).sub.m2O, CH(S.sub.pPa), CH.sub.2CH(S.sub.pPa), or (CH(S.sub.pPa)CH(S.sub.pPa)), Pa is a polymerizable group, B is an unsubstituted heterocycle, a substituted or unsubstituted crown ether group, or

##STR00002##

wherein T.sub.1 and T.sub.2 are each independently OH, CH.sub.3, CF.sub.3, CHF.sub.2, CH.sub.2F, CH.sub.2Br, CHBr.sub.2, CHCl.sub.2, or CH.sub.2Cl.

Compounds containing at least one CC triple bond of the formula I
R.sup.1-[A.sup.1-Z.sup.1].sub.m-A.sup.2A.sup.3-[Z.sup.2-A.sup.4].sub.n-[Z.sup.3-A.sup.5].sub.o-R.sup.2I,
which have neutral dielectric anisotropy, to the use thereof for high-frequency components, to liquid-crystalline media comprising the compounds, and to high-frequency components, in particular antennae, especially for the giga- and terahertz region, comprising these media. The liquid-crystalline media serve, for example, for the phase shifting of microwaves for tuneable phased-array antennae.

Nonlinear optical chromophore compositions which display lyotropic nematic liquid crystal phases in polar organic solvents and provide a mechanical anisotropic effect allowing for the formation of a non-centrosymmetric chromophore-polymer matrix without the application of an electric field.

The invention relates to bimesogenic compounds of formula I ##STR00001##
wherein R.sup.11, R.sup.12, MG.sup.11, MG.sup.12, X.sup.11, X.sup.12 and Sp.sup.1 have the meaning given in claim 1, to the use of bimesogenic compounds of formula I in liquid crystal media and particular to flexoelectric liquid crystal devices comprising a liquid crystal medium according to the present invention.

A dioxolane derivative represented by formula (G1) is provided. The explanation of the substituents is given in the specification. The use of the dioxolane derivative enables the production of a liquid crystal composition and a liquid crystal display device including the liquid crystal composition. ##STR00001##

Nonlinear optical chromophore compositions which display lyotropic nematic liquid crystal phases in polar organic solvents and provide a mechanical anisotropic effect allowing for the formation of a non-centrosymmetric chromophore-polymer matrix without the application of an electric field.

##STR00001##

Embodiments of the present disclosure discloses a liquid crystal composition and a display panel. The liquid crystal composition includes at least one first compound represented by formula (I). By adding the first compound to the liquid crystal composition, the performance of the liquid crystal composition is improved in terms of clearing point, elastic coefficient, and the like, thereby improving the display contrast and product quality of a display panel using the liquid crystal composition are improved.

The invention relates to a liquid-crystalline medium, in particular based on a mixture of polar compounds, and to the use thereof for an active-matrix display, in particular based on the VA, SA-VA, IPS, PS-IPS, FFS, PS-FFS, UB-FFS or PS-UB-FFS effect.