A liquid crystal display element having an improved response speed by using a liquid crystal compound having a high K.sub.33, while neither improving nor deteriorating all the characteristics as a liquid crystal display element. The liquid crystal display element 10 of the present invention has a first substrate 15, a second substrate 15, and a liquid crystal composition layer 5 interposed between the first substrate 15 and the second substrate 15, wherein at least one of the first substrate 15 and the second substrate 15 has an electrode that controls the liquid crystal composition layer 5 and the bend elastic constant K.sub.33 of at least one kind of liquid crystal compounds in the liquid crystal composition constituting the liquid crystal composition layer 5 is 20 pN or more.

A liquid crystal display element having an improved response speed by using a liquid crystal compound having a high K.sub.33, while neither improving nor deteriorating all the characteristics as a liquid crystal display element. The liquid crystal display element 10 of the present invention has a first substrate 15, a second substrate 15, and a liquid crystal composition layer 5 interposed between the first substrate 15 and the second substrate 15, wherein at least one of the first substrate 15 and the second substrate 15 has an electrode that controls the liquid crystal composition layer 5 and the bend elastic constant K.sub.33 of at least one kind of liquid crystal compounds in the liquid crystal composition constituting the liquid crystal composition layer 5 is 20 pN or more.

A coloring composition containing one or more species of compounds represented by Formula (I) or Formula (II) below, wherein each of R.sub.1 and R.sub.2 represents a hydrogen atom or substituent, each of Ar.sub.1 to Ar.sub.8 independently represents an optionally substituted aromatic hydrocarbon group or optionally substituted heterocyclic group, and each of L.sub.1 and L.sub.2 independently represents a divalent linking group which interrupts ? electron conjugated system: ##STR00001##

A coloring composition containing one or more species of compounds represented by Formula (I) or Formula (II) below, wherein each of R.sub.1 and R.sub.2 represents a hydrogen atom or substituent, each of Ar.sub.1 to Ar.sub.8 independently represents an optionally substituted aromatic hydrocarbon group or optionally substituted heterocyclic group, and each of L.sub.1 and L.sub.2 independently represents a divalent linking group which interrupts ? electron conjugated system: ##STR00001##

One purpose of the present invention is to provide a liquid-crystal compound which exhibits liquid crystallinity at low temperatures. Another purpose of the present invention is to provide a thermally responsive material which exhibits liquid crystallinity and rubber elasticity at low temperatures (around room temperature) ever, though a large amount of a liquid-crystal compound is contained therein, and a method for producing this thermally responsive material. A liquid-crystal compound according to the present invention is obtained by adding an alkylene oxide and/or styrene oxide to a mesogenic group-containing compound that has an active hydrogen group.

An optically anisotropic layer including a polymer and a compound having a mesogen skeleton, wherein the polymer has a property such that a film of the polymer that is formed by a coating method using a solution of the polymer satisfies nz(P)>nx(P)?ny(P), wherein nx(P) is a refractive index in a direction which, among in-plane directions of the film, gives a maximum refractive index, ny(P) is a refractive index in a direction which is perpendicular to the direction of nx(P) among the in-plane directions of the film, and nz(P) a refractive index in a thickness direction of the film, and the compound having a mesogen skeleton shows an in-plane retardation with reverse wavelength distribution under specific conditions.

An optically anisotropic layer including a polymer and a compound having a mesogen skeleton, wherein the polymer has a property such that a film of the polymer that is formed by a coating method using a solution of the polymer satisfies nz(P)>nx(P)?ny(P), wherein nx(P) is a refractive index in a direction which, among in-plane directions of the film, gives a maximum refractive index, ny(P) is a refractive index in a direction which is perpendicular to the direction of nx(P) among the in-plane directions of the film, and nz(P) a refractive index in a thickness direction of the film, and the compound having a mesogen skeleton shows an in-plane retardation with reverse wavelength distribution under specific conditions.

Provided is a polymer that includes a predetermined structural unit derived from an azomethine derivative having a polymerizable group and is reversibly fluidized and non-fluidized by being irradiated with light.

Provided is a polymer that includes a predetermined structural unit derived from an azomethine derivative having a polymerizable group and is reversibly fluidized and non-fluidized by being irradiated with light.

It is an object of the present invention to provide a compound that can provide a liquid crystal composition with a high T.sub.ni, a high ?n, a low V.sub.th, a high ??.sub.r, a low tan ?.sub.iso, and high storage stability at low temperatures, a liquid crystal composition, as well as a liquid crystal display element, a sensor, a liquid crystal lens, optical communication equipment, and an antenna each using this. Specifically disclosed are a compound represented by the general formula (i) having an ethynylene group (C?C) and an isothiocyanate group (NCS) and a liquid crystal composition containing one or two or more of the compounds.