Compounds of the formula I-A in which rings A, B in each case independently denote a ring of the formula L in each case, independently of one another, denotes unbranched or branched alkyl, alkenyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, or denotes F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R 0 )R 00 or cycloalkyl having 3 to 6 C atoms, r1 denotes 0, r2 denotes 1, r3 denotes 1, r4 denotes 0 or 1, r5 denotes 0 or 1, P denotes a polymerisable group, Sp denotes a spacer group or a single bond, p1 denotes 1 or 2, R 1 denotes an alkyl radical having 1 to 25 C atoms, where, in addition, one or more CH 2 groups in this radical may in each case be replaced, independently of one another, by -CH=CH-, -C≡C-, -CF 2 O-, -OCF 2 -, -O-, -S-, -CO-, -CO-O- or -O-CO- in such a way that O/S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F or Cl, or denotes H or a group -Sp-P, R a denotes an anchor group of the formula or p denotes 1 or 2, q denotes 2 or 3, B denotes a substituted or unsubstituted ring system or condensed ring system, o denotes 0 or 1, X 1 , independently of one another, denotes OH, SH, NH 2 , NHR 11 , NR 11 2 , C(O)OH or -CHO, R 11 denotes alkyl having 1 to 12 C atoms, which may be linear or branched and in which H may be substituted by fluorine or alkoxy having 1 to 8 C atoms, Sp a , Sp c , Sp d in each case, independently of one another, denote a spacer group or a single bond, and Sp b denotes a tri- or tetravalent group. rings A, B in each case independently denote a ring of the formula L in each case, independently of one another, denotes unbranched or branched alkyl, alkenyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, in which, in addition, one or more H atoms may be replaced by F or Cl, or denotes F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R 0 )R 00 or cycloalkyl having 3 to 6 C atoms, r1 denotes 0, r2 denotes 1, r3 denotes 1, r4 denotes 0 or 1, r5 denotes 0 or 1, P denotes a polymerisable group, Sp denotes a spacer group or a single bond, p1 denotes 1 or 2, R 1 denotes an alkyl radical having 1 to 25 C atoms, where, in addition, one or more CH 2 groups in this radical may in each case be replaced, independently of one another, by -CH=CH-, -C≡C-, -CF 2 O-, -OCF 2 -, -O-, -S-, -CO-, -CO-O- or -O-CO- in such a way that O/S atoms are not linked directly to one another, and in which, in addition, one or more H atoms may be replaced by F or Cl, or denotes H or a group -Sp-P, R a denotes an anchor group of the formula or p denotes 1 or 2, q denotes 2 or 3, B denotes a substituted or unsubstituted ring system or condensed ring system, o denotes 0 or 1, X 1 , independently of one another, denotes OH, SH, NH 2 , NHR 11 , NR 11 2 , C(O)OH or -CHO, R 11 denotes alkyl having 1 to 12 C atoms, which may be linear or branched and in which H may be substituted by fluorine or alkoxy having 1 to 8 C atoms, Sp a , Sp c , Sp d in each case, independently of one another, denote a spacer group or a single bond, and Sp b denotes a tri- or tetravalent group. <EOS>