Bimesogenic compounds of formula I R 11 and R 12 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 CH 2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-, -NH-, -N(CH 3)-, -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, preferably F, Cl, CN, a straight-chain or branched alkyl group with 1 to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN more preferably a polar group, most preferably F, Cl, CN, OCF 3, CF 3, and at least one of R 11 and R 12 is an alkenyl group or an alkinyl group either straight-chain or branched, with 2 to 25 C atoms, preferably with 2 to 7 C atoms, which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH 2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-,-NH-, -N(CH 3)-, -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, MG 11 and MG 12 are each independently a mesogenic group, at least one of MG 11 and MG 12 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, preferably selected from the group of linking groups -CO-O-, -O-CO-, -CH 2 -O-, -O-CH 2 -, -CF 2 -O- and -O-CF 2 -, Sp 1 is a spacer group comprising 1, 3 or 5 to 40 C atoms, wherein one or more non-adjacent and non-terminal CH 2 groups may also be replaced by -O-, -S-, -NH-, -N(CH 3)-, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CH(halogen)-, -CH -, -CH=CH- or -C≡C-, however in such a way that no two O-atoms are adjacent to one another, now two -CH=CH- groups are adjacent to each other and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other, preferably -CH 2) n - (i.e. 1,n-alkylene with n C atoms), with n an integer, preferably from 3 to 19, more preferably from 3 to 11, most preferably an odd integer (i.e. 3, 5, 7, 9 or 11), X 11 and X 12 are independently from one another a linking group selected from -CO-O-, -O-CO-, -O-, -CH=CH-, -C≡C-, -CF 2 -O-, -O-CF 2 -, -CF 2 -CF 2, -CH 2 -O-, -O-CH 2 -, -CO-S-, -S-CO-, -CS-S-, -S-, and a single bond, preferably -CO-O-, -O-CO- or a single bond, most preferably a single bond, however under the condition that in -X 11 -Sp 1 -X 12 - no two O atoms are adjacent to one another, no two -CH=CH- groups are adjacent to each other and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other. R 11 and R 12 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 CH 2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-, -NH-, -N(CH 3)-, -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, preferably F, Cl, CN, a straight-chain or branched alkyl group with 1 to 25 C atoms which may be unsubstituted, mono- or polysubstituted by halogen or CN more preferably a polar group, most preferably F, Cl, CN, OCF 3, CF 3, and R 11 and R 12 is an alkenyl group or an alkinyl group either straight-chain or branched, with 2 to 25 C atoms, preferably with 2 to 7 C atoms, which may be unsubstituted, mono- or polysubstituted by halogen or CN, it being also possible for one or more non-adjacent CH 2 groups to be replaced, in each occurrence independently from one another, by -O-, -S-,-NH-, -N(CH 3)-, -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, MG 11 and MG 12 are each independently a mesogenic group, MG 11 and MG 12 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, preferably selected from the group of linking groups -CO-O-, -O-CO-, -CH 2 -O-, -O-CH 2 -, -CF 2 -O- and -O-CF 2 -, Sp 1 is a spacer group comprising 1, 3 or 5 to 40 C atoms, wherein one or more non-adjacent and non-terminal CH 2 groups may also be replaced by -O-, -S-, -NH-, -N(CH 3)-, -CO-, -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O-, -CH(halogen)-, -CH -, -CH=CH- or -C≡C-, however in such a way that no two O-atoms are adjacent to one another, now two -CH=CH- groups are adjacent to each other and no two groups selected from -O-CO-, -S-CO-, -O-COO-, -CO-S-, -CO-O- and -CH=CH- are adjacent to each other, preferably -CH 2) n - (i.e. 1,n-alkylene with n C atoms), with n an integer, preferably from 3 to 19, more preferably from 3 to 11, most preferably an odd integer (i.e. 3, 5, 7, 9 or 11), X 11 and X 12 are independently from one another a linking group selected from -CO-O-, -O-CO-, -O-, -CH=CH-, -C≡C-, -CF 2 -O-, -O-CF 2 -, -CF 2 -CF 2, -CH 2 -O-, -O-CH 2 -, -CO-S-, -S-CO-, -CS-S-, -S-, and a single bond, preferably -CO-O-, -O-CO- or a single bond, most preferably a single bond,