1,4-disubstituted 2,6-difluorobenzene compound of formula I wherein R is an alkyl or alkenyl radical, A1 and A2, in each case independently of one another, are (a) a trans-1,4-cyclohexylene radical in which a CH2 group may be replaced by —O— and/or —S, (b) a 1,4-phenylene radical in which a CH group may be replaced by N, (c) 1,4-cyclohexenylene, 1,4-bicyclo(2,2,2)octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, Z1 and Z2 are —CO—O—, —O—CO—, —CH2—O—, —OCH2—, —CH2CH2—, —CH═CH—, —C≡C— or a single bond m and n are 0, 1, 2 or 3, (m+n) is 1, 2 or 3, X is R or F, Cl, CF3, —OCF3, or —OCHF2, —OCF5, —CN or —NCS with the proviso that at least one of the radicals A1 and A2 present in the molecule is are suitable as components of liquid-crystalline media.