Abstract: Compounds of formula (I) where R is C.sub.1-15 alkyl, X is hydrogen, fluorine or chlorine, m and n are independently selected 1 or 0, W is C.sub.1-15 alkyl or alkoxy, CN or halogen, rings A and B Are independently selected from phenyl, laterally fluoro- or chloro- substituted phenyl, transcyclohexyl pyridyl, pyrimidyl or dioxanyl. Preferred embodiments have R=C.sub.3-8 and where W is alkyl or alkoxy then it is also preferable that W=C.sub.3-8. Where m=0, then preferably W=CN and where m=1, then preferably W=alkyl.

Abstract: The invention relates to thermochromic liquid crystalline phases with at least two components, characterized in that at least one component is an optically active compound of the formula I ##STR1## wherein R.sup.1 and R.sup.2 are each independently a chiral residue, importing to the phase a tight helical twist. ##STR2## denotes a 1,4-phenylene group optionally substituted by fluorine, X.sup.1 and X.sup.2 are each independently O or NH,n is 1, 2 or 3 andm is 0 or 1, which can be used in electro-optic devices, in temperature indicating devices or for color-changing cosmetics.

Abstract: Optically active naphthalene compounds having the formula: ##STR1## in which X and Y are selected from combinations (a), (b) and (c): (a) X is C.sub.1-10 alkyl or alkoxy and Y is C.sub.4-16 optically active alkyl, (b) X is C.sub.1-10 alkyl or alkoxy and Y is ##STR2## where R.sup.2 is C.sub.4-16 optically active alkyl, (c) X is ##STR3## where R.sup.1 is C.sub.1-10 alkyl or alkoxy and Y is C.sub.4-16 optically active alkyl. Ferroelectric smectic liquid crystal materials being compositions containing these compounds are also described.

Abstract: Biphenyl egters of formula (I), ##STR1## wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is O or 1 R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is O and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: The invention relates to ferroelectric smectic liquid crystal mixtures and compounds. The invention also relates to electro-optical devices incorporating these mixtures.

Abstract: Biphenyl esters of formula (I), wherein formula (II) represents formula (III) or formula (IV), R.sub.1 represents C.sub.3 -C.sub.12 alkyl, alkoxy, alkylcarbonyloxy, alkoxycarbonyl or alkoxycarbonyloxy, j is 0 or 1, R.sub.2 represents C.sub.3 -C.sub.12 alkyl or alkoxy, one of Q.sub.1 or Q.sub.2 is fluorine and the other is hydrogen, provided that when j is 0 and formula (II) is formula (III) and both R.sub.1 and R.sub.2 are n-alkyl, then the total number of carbon atoms in R.sub.1 and R.sub.2 is more than 12. These compounds may be used as constituents of liquid crystal mixtures which show a room temperature ferroelectric smectic phase, and a number of such mixtures are described.

Abstract: Disubstituted ethanes having a formula ##STR1## wherein R is alkyl, X is selected from hydrogen, ##STR2## wherein each R.sub.1 is selected from H, alkyl, alkoxy, halo and cyano and each of Q.sub.1, Q.sub.2, Q.sub.3 and Q.sub.4 is independently selected from H and F are useful as components of liquid crystal materials for electro-optical displays and compounds useful in the production of such components.

Abstract: An intermediate useful in the production of liquid crystal esters has a molecular structure ##STR1## in which of the groups R' and R" one is fluorine and the other is hydrogen, and in which R is an alkyl group having more than one carbon atom, an aryl substituted alkyl group or a cyclohexyl substituted alkyl group.These compounds may be prepared from the corresponding alkoxy compounds ##STR2## where R'" is a protective alkyl group such as methyl. These compounds may be used in the production of liquid crystal esters by a conventional esterification with carboxylic acids, or acid derivative, eg chloride, eg containing the radical ##STR3## where X is an alkyl group and ##STR4## is a benzene or cyclohexane ring.