Liquid-crystalline medium

Liquid-crystalline medium having negative dielectric anisotropy based on a mixture of polar compounds, which comprises at least one compound of the formula I

• in which
• R11 denotes an alkyl or alkenyl radical having up to 4 C atoms which is unsubstituted, monosubstituted by CN or CF3 or at least mono-substituted by halogen, where, in addition, one or more CH2 groups in these radicals may be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
• R12 denotes an alkenyl radical having up to 5 C atoms which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups in these radicals may be replaced by —O—, —S—,
• —C≡C—, —CF2O—, —OCF2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another,
• in amounts of ≧30% by weight, based on the medium.