Compounds of the formula I in which R 1 denotes branched or unbranched alkyl having 1 to 15 C atoms or branched or unbranched alkenyl having 2 to 15 C atoms, where, in addition, one or more non-adjacent "-CH2-" groups in these radicals may be replaced by -O- and/or one or more H atoms may be replaced by halogen atoms, X 1 denotes F, Cl, fluorinated alkyl having 1 to 4 C atoms, fluorinated alkoxy having 1 to 4 C atoms, fluorinated alkenyl having 2 to 4 C atoms, fluorinated alkenyloxy having 2 to 4 C atoms, CN, NCS or SF 5, L 11 and L 13 in each case, independently of one another, denote branched or unbranched alkyl having 1 to 12 C atoms, branched or unbranched alkenyl or alkynyl having 2 to 12 C atoms, substituted or unsubstituted cycloalkyl, cycloalkenyl, and alternatively L 13 also denotes H, L 12 and L 14 in each case, independently of one another, denote F, Cl, CN, branched or unbranched alkyl having 1 to 12 C atoms, branched or unbranched alkenyl or alkynyl having 2 to 12 C atoms, substituted or unsubstituted cycloalkyl, cycloalkenyl, fluorinated alkyl or fluorinated alkoxy, each having 1 to 12 C atoms, fluorinated alkenyl or fluorinated alkenyloxy, each having 2 to 12 C atoms, alternatively L 14 also denotes H, and on each occurrence, independently of one another, denote 1,4-phenylene, 1,4-naphthylene, 2,6-naphthylene, 1,4-anthracenylene, 2,6-anthracenylene, 2,7-pyrenylene, 2,7-phenanthrenylene, where the ring systems may likewise be substituted as desired by the substituents L 11, Z 1 on each occurrence, independently of one another, denotes a single bond, -C≡C-, -CF=CF- or -CH=CH-, n denotes 1 or 2. R 1 denotes branched or unbranched alkyl having 1 to 15 C atoms or branched or unbranched alkenyl having 2 to 15 C atoms, where, in addition, one or more non-adjacent "-CH2-" groups in these radicals may be replaced by -O- and/or one or more H atoms may be replaced by halogen atoms, X 1 denotes F, Cl, fluorinated alkyl having 1 to 4 C atoms, fluorinated alkoxy having 1 to 4 C atoms, fluorinated alkenyl having 2 to 4 C atoms, fluorinated alkenyloxy having 2 to 4 C atoms, CN, NCS or SF 5, L 11 and L 13 in each case, independently of one another, denote branched or unbranched alkyl having 1 to 12 C atoms, branched or unbranched alkenyl or alkynyl having 2 to 12 C atoms, substituted or unsubstituted cycloalkyl, cycloalkenyl, and alternatively L 13 also denotes H, L 12 and L 14 in each case, independently of one another, denote F, Cl, CN, branched or unbranched alkyl having 1 to 12 C atoms, branched or unbranched alkenyl or alkynyl having 2 to 12 C atoms, substituted or unsubstituted cycloalkyl, cycloalkenyl, fluorinated alkyl or fluorinated alkoxy, each having 1 to 12 C atoms, fluorinated alkenyl or fluorinated alkenyloxy, each having 2 to 12 C atoms, alternatively L 14 also denotes H, and on each occurrence, independently of one another, denote 1,4-phenylene, 1,4-naphthylene, 2,6-naphthylene, 1,4-anthracenylene, 2,6-anthracenylene, 2,7-pyrenylene, 2,7-phenanthrenylene, where the ring systems may likewise be substituted as desired by the substituents L 11, Z 1 on each occurrence, independently of one another, denotes a single bond, -C≡C-, -CF=CF- or -CH=CH-, n denotes 1 or 2.