Cyanostilbenes

Compounds according to the general formula (I)

• wherein
• Ar1 and Ar2 are independently from each other a ring system of 4 to 40 atoms, wherein each ring system includes at least one unsaturation directly connected via electron conjugation (π-π bonding) to the double bond shown in formula (I), wherein the ring system is unsubstituted or mono- or poly-substituted by a halogen atom and/or a polar group like hydroxy, nitro, nitrile, —CF3;
• or by a carboxy group, and/or a cyclic, straight-chain or branched alkyl residue having from 1 to 30 carbon atoms, which is unsubstituted, mono- or poly-substituted by methyl, fluorine and/or chlorine, wherein one or more, preferably non-adjacent —CH2— groups independently may be replaced by a group selected from —O—, —CO— —CO—O—, —O—CO—, —NR1′—, —NR1′—CO—, —CO—NR1′—, —NR1′—CO—O—, —O—CO—NR1′—, —NR1′—CO—NR1′, —CH═CH—, —C≡C—, —O—CO—O— and —Si(CH3)2—O—Si(CH3)2—, an aromatic or an alicyclic group, wherein R1′ is a hydrogen atom or lower alkyl;
• and/or an acryloyloxy, alkoxy, alkylcarbonyloxy, alkyloxocarbonyloxy, methacryloyloxy, vinyl, allyl, vinyloxy and/or allyloxy group, having from 1 to 20 carbon atoms, preferably having from 1 to 10 carbon atoms;
• preferably the ring system is unsubstituted or substituted by an alkoxy group;
• and wherein;
• if X is hydrogen and Y is CN,
• then R1, R2 or R3 are independently from each other hydrogen, halogen or —CF3, with the proviso that R1, R2 or R3 are not simultaneously hydrogen;
• if X is CN and Y is hydrogen;
• then R1, R2 or R3 are independently from each other hydrogen, halogen or —CF3;
• M is a single covalent bond or a spacer unit;
• Y1, Y2 are independently from each other a bridging group,
• P is a hydrogen atom, optionally substituted alkyl, or a polymerizable group.