NEW MATERIAL:A compound expressed by formula I (R2 is H or 1W15C straight-chain or branched alkyl; R2 is 3W15C alkyl straight-chain or branched alkyl having one double bond or alkoxy).

EXAMPLE: 1-Allyloxy-4-(trans-4-propylcyclohexyl-trans-4-cyclohexyl)benzene.

USE: A liquid crystal compound having large K3/K1 and low viscosity and exhibiting a liquid crystal phase at wide temperature range.

PREPARATION: A compound expressed by formula II is reacted with an alkenyl bromide expressed by the formula R2Br in the presence of KOH in ethanol to provide the compound expressed by formula I (R2 is alkoxy). A compound expressed by formula III is reacted with an alkenyl magnesium bromide expressed by the formula R2MgBr in the presence of bis(1,2-diphenylphosphino) ethane nickel (II) chloride to provide the compound expressed by formula I (R2 is alkyl).