R¹: is H or a linear or branched alkyl group of 1 to 20 or a linear or branched alkenyl group of 2 to 20 C atoms, wherein in either case optionally one —CH₂— group being replaced by cyclohexylen-1,4-diyl, or one or two —CH₂— groups optionally being replaced by —O—, if non-adjacent to N, or by —C(═O)—, —Si(CH₃)₂—,

and/or one or more H of the alkyl or alkenyl group optionally being replaced by F or CH₃;

R²: stands for

a) H or F,

b) a linear or branched alkyl group of 1 to 20 or a linear or branched alkenyl group of 2 to 20 C atoms, wherein in either case one or two —CH₂— groups optionally being replaced by —O—, —C(═O)O—, —Si(CH₃)₂—, and/or one or more H of the alkyl or alkenyl group being replaced by F or CH₃,

c) a radical

wherein independently from the respective meanings in (I)

R³, R⁴, R⁵, R⁶: are independently from another an alkyl group of 1 to 8 C atoms;

M¹, M²: represent independently from another a single bond, —OC(═O)—, —C(═O)O—, —OCH₂—, —NH—;

A: is

a) a linear or branched alkan-α,ω-diyl group of 1 to 20 or alkene-α,ω-diyl group of 2 to 20 C atoms, optionally, if non-adjacent to M¹ and M², one or two non-adjacent —CH₂— groups may be replaced by —O—,

b) the group —C(═Y)— wherein Y is CH-Z with Z being phenylen-1,4-diyl, optionally substituted by one to three halogen atoms, alkyl or alkyloxy groups of 1 to 4 C atoms, with the proviso that M¹ and M² are —C(═O)O— and —OC(═O)—,

c) the group —CHY wherein Y is CH₂-Z with Z being phenylen-1,4-diyl, optionally substituted by one to three halogen atoms, alkyl or alkyloxy groups of 1 to 4 C atoms, with the proviso that M¹ and M² are —C(═O)O— and —OC(═O)—,

d) a group

wherein p, q are 1 or 2, the sum of p+q being ≧1;

M³ is a single bond or —OC(═O)—, —C(═O)O—, —OCH₂—, —CH₂O—, —C≡C—, —CH₂CH₂—, —CH₂CH₂CH₂CH₂—,

the radicals

are independently from another phenylen-1,4-diyl, which optionally can be substituted by one, two or three F, or cyclohexan-1,4-diyl, which can optionally be substituted by one CN, CH₃ or F, or pyrimidin-2,5-diyl, optionally substituted by one F, pyridine-2,5-diyl, which can optionally be substituted by one F, or naphthalene-2,6-diyl, which can optionally be substituted by one, two or three F, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl (the aromatic ring optionally substituted by one, two or three F), or decahydronaphthalene-2,6-diyl, or indane-2,5(6)-diyl, or fluorene-2,-7-diyl, or phenanthrene-2,7-diyl, or 9,10-dihydrophenanthrene-2,7-diyl, or (1,3,4)thiadiazol-2,5-diyl, or (1,3)thiazol-2,5-diyl, or (1,3)thiazol-2,4-diyl, or thiophen-2,4-diyl, or thiophen-2,5-diyl, or (1,3)dioxan-2,5-diyl, or piperidin-1,4-diyl, or piperazin-1,4-diyl;

X is H, OH, a linear or branched alkyl or alkyloxy group of 1 to 20 C atoms, wherein one or two —CH₂— groups can be replaced by —O—, —C(═O)O—, —Si(CH₃)₂—, optionally one or more H being replaced by F or CH₃;

m: is 0 or 1;

X and M¹-(A)_m-M²-R² together can constitute

a) a ring of 4 to 16 members, optionally substituted by an alkyl radical of 1 to 15 C atoms,

b) a combination of two either directly linked or spiro-linked rings of independently from another 4 to 16 members, optionally substituted by an alkyl radical of 1 to 15 C atoms in either of the three variants the rings independently from another being carbocycles or carbocycles comprising B, N, O or S heteroatoms.