Abstract: Provided are novel acetylene compounds which are useful as a component for a liquid crystal composition used for a liquid crystal element, a liquid crystal composition containing said compounds and a liquid crystal element using said liquid crystal composition. The acetylene compound is represented by Formula (1): n-CmH2m+1—C≡C—A—Z1—B—Y1—R1  (1) wherein m represents an integer of 2 to 24; R1 represents a linear or branched alkyl group, a linear or branched alkoxyalkyl group, a linear or branched alkenyl group, or a linear or branched alkenyloxyalkyl group each of which may be substituted with a halogen atom; R1 may have an asymmetric carbon atom, and the asymmetric carbon atom may be optically active; A and B represents a cyclic group such as a phenylene group, a biphenylene group, a naphthylene group and the like each of which may be substituted with a halogen atom.

Abstract: Provided is a naphthalene compound represented by the following Formula (1): ##STR1## wherein R.sub.1 and R.sub.2 each represent a linear or branched alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group having 2 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms which may be substituted with halogen atoms and have no asymmetric carbon atoms; A represents any of the groups represented by the following formulas: ##STR2## (wherein X.sub.1, X.sub.2, X.sub.3 and X.sub.4 each represent a hydrogen atom or a halogen atom); and z represents 0 or 1. The addition of this naphthalene compound to a liquid crystal composition makes it possible to improve various characteristics such as the high speed response property of the liquid crystal composition and the temperature dependency of the response time. The above naphthalene compound is useful as a liquid crystal material for liquid crystal compositions, particularly ferroelectric liquid crystal compositions.

Abstract: A novel pyrimidine compound represented by the following Formulas (1) and (2), a liquid crystal composition containing said compound and a liquid crystal element having excellent characteristics such as high speed response, orientation and high contrast ratio. ##STR1## wherein R.sub.1 and R.sub.2 each represent a linear or branched alkyl or alkenyl group, an alkoxyl or alkenyloxy group; R.sub.3 and R.sub.4 each represent a linear or branched alkyl group or alkenyl group; A.sub.1 and A.sub.2 each represent a substituted or unsubstituted 1,4-phenylene group, a pyridine-2,5-diyl or trans-1,4-cyclohexylene group; X.sub.1 and X.sub.2 each represent a single bond, --COO--, --OCO--, --OCH.sub.2 or --CH.sub.2 O-- group; Y.sub.1 and Y.sub.2 each represent --COO-- or --OCO-- group; and a, b, p, q, m and n each represent 0 or 1, provided that a+b+p+q is not 0.