Liquid-crystalline medium and electro-optical liquid-crystal display

A liquid-crystalline medium having positive dielectric anisotropy, comprising a compound of formula I2a-1

• a compound of formula I2a-3
• and a compound of formula I2b-1
• and optionally at least one compound of formula I1 or I3,
• in which
• R11 denotes an alkyl or alkenyl radical having up to 15 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—, —OC—O—, or —COO— in such a way that O atoms are not linked directly to one another,
• R11* denotes an unsubstituted alkyl or alkenyl radical having up to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may be replaced by —O—, —S—,
• —C≡C—, —OC—O—, or —COO— in such a way that O atoms are not linked directly to one another,
• Z0 denotes —COO—, —OCO—, —CH2O—, —OCH2—, —CF2—O—, —O—CF2—, —CH2—CH2—, —CF2—CF2—, —CFH—CFH—, —CH═CH—, —CF═CF—, —CF═CH—, —C≡C—, or —CH═CF—,
• Sp denotes O, an alkylene, alkyleneoxy, oxaalkylene or alkenylene radical having up to 6 C atoms which is unsubstituted or mono- or polysubstituted by halogen,
• p denotes 0 or 1,
• l and k denote 0 to 5,
• further comprising at least one compound of formula IIg,
• in which
• R21 is an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, or monosubstituted by CN or CF3 or at least monosubstituted by halogen, where, in addition, one or more CH2 groups may be replaced by —O—, —S—,
• —C≡C—, —OC—O—, or —O—CO— in such a way that O atoms are not linked directly to one another,
• at least one compound of formula, and
• at least one compound of formula VI-5,
• in which
• R61 denotes an unsubstituted alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in this radical may each be replaced, independently of one another, by —C≡C—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —(CO)O—, —O(CO)—, —(CO)— or —O— in such a way that O atoms are not linked directly to one another,
• X61 denotes F, Cl, CN or alkyl, alkenyl, alkenyloxy, alkylalkoxy or alkoxy having 1 to 3 C atoms which is mono- or polysubstituted by F.