TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The structural unit (I) is a structural unit comprising an amino derivative of formula (T-Ar2-N(Ar4)-Ar3-(Ar5)m-(N(Ar7)-Ar6)n-T) (II), preferably 4-formyl-triphenylamine-4',4''-diyl, N1,N4-bis(p-formyl-phenyl)-N1,N4-diphenyl-benzene-1,4-diamine-4,4''-diyl and N1-(p-formyl-phenyl)-N1,N4,N4-triphenyl-benzene-1,4-diamine-4,4''-diyl. The group Ar1 in (I) and Ar3 and/or Ar6 in (II) exhibits an aldehyde group.Ar2, Ar3, Ar5, Ar6 = optionally substituted, mono- or polycyclic, aromatic or heteroaromatic ring system with 5-25 ring atoms (where, at least one group of Ar2-Ar7 exhibits an aldehyde group), preferably optionally substituted 4,5-dihydropyrene, 4,5,9,10-tetrahydrofluorene, 9,9'-spirobifluorene, fluorene, phenanthrene, 9,10-dihydrophenanthrene, 5,7-dihydrodibenzoxepin, cis-indenofluorene, trans-indenofluorene, phenylene, thiophene, benzanthracene, carbazole, benzimidazole, oxepin or triazine;Ar4, Ar7 = optionally substituted, mono- or polycyclic, aromatic or heteroaromatic ring system with 5-25 ring atoms (where, at least one group of Ar2-Ar7 exhibits an aldehyde group);m = 0 or 1;n = 0-2; andT = bond to the next structural unit of the polymer.Provided that: when n is 1, the two nitrogen atoms are bonded to different carbon atoms of the same aromatic ring system.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Disclosed): The preparation of the polymer comprises polymerizing the monomers having the end groups comprising halogen (preferably bromine and iodine), O-tosylate, O-triflate, a sulfonic acid derivative of formula (O-SO2R1), an organoboron derivative of formula (B(OR1)2) or an organotin derivative of formula (Sn(R1)3) by Suzuki polymerization, Yamamoto polymerization, Stille polymerization or Hartwig-Buchwald polymerization.R1 = H, 1-20C aliphatic hydrocarbon (preferably optionally branched alkyl, alkenyl or alkynyl, in which at least one C is replaced by O, N or S and at least one H is replaced by F), aromatic mono- or polycyclic ring system with 6-20C ring atoms (preferably phenyl); orR1R1 = ring system.Preferred Components: The polymer comprises an additional structural unit, which is different from the structural units (I) and/or (II). The additional structural unit is a structural unit (I) and/or (II), which does not exhibits an aldehyde group. Preferred Definitions:    Ar1 = optionally substituted phenylene, biphenylene, triphenylene, (1,1':3',1'')terphenyl-2'-ylene, naphthylene, anthracene, binaphthyl, phenanthrene, dihydrophenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzo(a)pyrene, fluorene, indene, indenofluorene, spirobifluorene, pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthreneimidazole, pyridimidazole, pyrazineimidazole, quinoxalineimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno(2,3b)thiophene, thieno(3,2b)thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene or benzothiadiazothiophene; and    Ar = optionally substituted 4,5-dihydropyrene, 4,5,9,10-tetrahydrofluorene, 9,9'-spirobifluorene, fluorene, phenanthrene, 9,10-dihydrophenanthrene, 5,7-dihydrodibenzoxepin, cis-indenofluorene, trans-indenofluorene, phenylene, thiophene, benzanthracene, carbazole, benzimidazole, oxepin or triazine.    EXAMPLE - No suitable example given.