Bimesogenic compounds and mesogenic media

Bimesogenic compounds of formula I

• wherein
• R11 and R12 are each independently H, F, Cl, CN, NCS or a straight-chain or branched alkyl group with 1 to 25 C atoms, which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH2 groups to be replaced, in each occurrence independently from one another, by —O—, —S—,
• —NH—, —N(CH3)—, —CO—, —COO—, —OCO—, —O—CO—O—, —S—CO—, —CO—S—, —CH═CH—, —CH═CF—, —CF═CF— or —C≡C— in such a manner that oxygen atoms are not linked directly to one another, a straight-chain or branched alkyl group with 1 to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN,
• MG11 and MG12 are each independently a mesogenic group,
• at least one of
• MG11 and MG12 comprises one, two or more 5-atomic and/or 6-atomic rings, in case of comprising two or more 5- and/or 6-atomic rings at least two of these may be linked by a 2-atomic linking group, and
• CG1 is a central group, having a total length of three atoms,
• however under the condition that the following compounds are excluded from formula I
• and compounds comprising the a moiety selected from the following group of moieties
• are excluded from the compounds of formula I.