Abstract: A novel tolan compound of the formula (I): wherein A is C1-10 alkyl, C1-10 alkoxy, cyclohexyl substituted by C1-10 alkyl at 4 position, cyclohexyl substituted by C1-10 alkoxy group at 4 position or a group of the formula: wherein Y is hydrogen or halogen and Z is C1-10 alkyl or halogen; B is a single bond or —CO—O— or —O—CO—; D is hydrogen, C1-10 alkyl, cyclohexyl substituted by C1-10 alkyl at 4 position; and Z represents a hydrogen atom or a halogen atom. The tolan compound can increase the N-I point, decrease the viscosity, and increase the double refractive index of a liquid crystal composition without affecting the viscosity and threshold voltage Vth, and is mutually soluble with various other liquid crystal compounds, so that the compound can be used as a constituent of a liquid crystal composition in combination with these other liquid crystal materials to improve the properties of the composition.

Abstract: A novel tolan compound of the formula (I): ##STR1## wherein A is C.sub.1-10 alkyl, C.sub.1-10 alkoxy, cyclohexyl substituted by C.sub.1-10 alkyl at 4 position, cyclohexyl substituted by C.sub.1-10 alkoxy group at 4 position or a group of the formula: ##STR2## wherein Y is hydrogen or halogen and Z is C.sub.1-10 alkyl or halogen; B is a single bond or --CO--O-- or --O--CO--; D is hydrogen, C.sub.1-10 alkyl, cyclohexyl substituted by C.sub.1-10 alkyl at 4 position; and Z represents a hydrogen atom or a halogen atom. The tolan compound can increase the N-I point, decrease the viscosity, and increase the double refractive index of a liquid crystal composition without affecting the viscosity and threshold voltage Vth, and is mutually soluble with various other liquid crystal compounds, so that the compound can be used as a constituent of a liquid crystal composition in combination with these other liquid crystal materials to improve the properties of the composition.

Abstract: A novel tolan compound of the formula (I): ##STR1## wherein A is a substituted or unsubstituted cyclohexyl or phenyl group; B is --CO--O-- or --O--CO--; X is a hydrogen atom, a halogen atom, a cyano group, a C.sub.1 -C.sub.10 alkyl group, or a C.sub.1 -C.sub.10 alkoxy group; Y is a hydrogen atom or a halogen atom; and m and n are an integer of 0 or 1, provided that m+n=0 or 1. The tolan compound can raise the N-I point and increase the double refractive index (.DELTA.n) of liquid crystal compositions. The liquid crystal composition containing this tolan compound has excellent characteristics as a liquid crystal material, and the liquid crystal display device using this liquid crystal composition has a wide temperature range and a wide visible angle and can be operated at a low driving voltage.

Abstract: Disclosed are a benzyl ether derivative represented by the following formula (I), useful as a liquid crystal display material, and a liquid crystal composition containing the same and a liquid crystal display device utilizing the composition. ##STR1## [wherein A represents a 4-alkylcyclohexyl group or an alkyl group, B represents a di- or tri-fluorophenyl group, a 4-(di- or tri-fluorophenyl)phenyl group, a 4-alkylphenyl group or a 4-alkoxyphenyl group].The compound (I) of the present invention has good compatibility with other compounds, and can be used in a liquid crystal composition by combining with many liquid crystal materials as a constitutional component of the liquid crystal composition. It has functions of lowering a C-N point of a liquid crystal composition, lowering a threshold voltage by enlarging a dielectric anisotropy, and also lowering a viscosity and increasing a N-I point of the liquid crystal composition.

Abstract: An ester derivative represented by the following formula (I). ##STR1## In the formula, V, W, X, Y and Z represent a hydrogen atom or a halogen atom, respectively. The present invention also comprises a liquid crystal composition containing the ester derivative. The ester derivative can optimize the n value, lower the viscosity and reduce the threshold voltage Vth of the liquid crystal composition.

Abstract: A nematic liquid crystal composition comprising at least one member selected from 4-alkyl- or 4-alkoxy-benzoic acids represented by the following general formula (I) , particularly a nematic liquid crystal composition comprising a carboxylic acid mixture composed of at least one member selected from 4-alkyl- or 4-alkoxy-benzoic acids represented by the following general formula (I) and at least one member selected from 4-alkylcyclohexanecarboxylic acids represented by the following general formula (IV): ##STR1## wherein R.sub.1 stands for an alkyl or alkoxy group having 1 to 12 carbon atoms and R.sub.4 stands for an alkyl group having 1 to 12 carbon atoms.

Abstract: Particular 1,4-substituted dihydrobenzene derivatives are useful as liquid crystalline materials. They are represented by the following formula (I): ##STR1## wherein A means a 1,4-dihydrophenylene group, R denotes a hydrogen atom or an alkyl or trans-4-alkylcyclohexyl group, R' represents a hydrogen or halogen atom, a trifluoromethyl, trifluoromethoxy, cyano, alkyl, alkoxyl or carboxyl group or a group --COO--B--R" in which B stands for an unsubstituted or halogen-substituted 1,4-phenylene or 1,4-cyclohexenylene group and R" represents a halogen atom or a cyano, alkyl or alkoxyl group, and X, Y and Z individually mean a hydrogen or halogen atom.