NOVELTY - Polymer comprising at least one triarylamine structural unit (I) and at least one aryl structural unit (II), is new. (I) or (II) exhibits at least one crosslinkable group.    USE - The polymer is useful for preparing a crosslinked polymer, which is useful in an active layer of electronic or optoelectronic components, preferably electronic or optoelectronic devices comprising organic electroluminescent devices, organic light-emitting electrochemical cells, organic field-effect transistors, organic integrated circuits, organic thin-film transistors, organic solar cells, organic laser diodes, organic photovoltaic elements or devices, and organic photoreceptors, preferably organic electroluminescent devices (all claimed).    ADVANTAGE - The polymer increases voltage, efficiency and service life of the organic electroluminescent devices, and exhibits sufficient degree of crosslinking.    DETAILED DESCRIPTION - Polymer comprising at least one triarylamine structural unit of formula (-Ar2-N(Ar1)-Ar3) (I) and at least one aryl structural unit of formula (II), is new. (I) or (II) exhibits at least one crosslinkable group.    Either i, j = 0 or 1; or    i+j = 1; either    R = 1-40C alkyl or 1-40C (thio)alkoxy (both linear) or 3-40C alkyl or 3-40C (thio)alkoxy (both branched or cyclic) or 2-40C alkenyl or 2-40C alkynyl (where in all groups at least one non-adjacent CH2 group is optionally replaced by R1C=CR1, CC, Si(R1)2, C=O, C=S, C=NR1, P(=O)(R1), SO, SO2, NR1, O, S or CONR1, and at least one H is optionally replaced by D, F, Cl, Br, I or CN), (hetero)aromatic ring with 5-60 aromatic ring atoms, (hetero)aryloxy with 5-60 aromatic ring atoms, (hetero)aralkyl with 5-60 aromatic ring atoms, diarylamino with 10-40 aromatic ring atoms, diheteroarylamino with 10-40 aromatic ring atoms or aryl-heteroaryl-amino with 10-40 aromatic ring atoms (all optionally substituted by at least one group R1), H, D, F, Cl, Br, I, N(R1)2, CN, NO2, Si(R1)3, B(OR1)2, C(=O)R1, P(=O)(R1)2, S(=O)R1, S(=O)2R1 or OSO2R1; or    at least 2 R = mono- or polycyclic and aliphatic, aromatic and/or benzo-fused ring; either    R1 = aliphatic or (hetero)aromatic 1-20C hydrocarbyl (in which at least one H is optionally replaced by F), H, D or F; or    at least 2 R1 = mono- or polycyclic and aliphatic or aromatic ring; and    Ar1-Ar8 = mono- or polycyclic (hetero)aromatic ring (optionally substituted by at least one group R).    INDEPENDENT CLAIMS are also included for:    (1) preparing the polymer;    (2) a polymer blend comprising at least one above crosslinkable polymer, and at least one further polymeric-, oligomeric-, dendritic- and/or low molecular weight substance;    (3) a solution or formulation comprising the crosslinkable polymer or the polymer blend in at least one solvent;    (4) preparing a crosslinked polymer, comprising (a) providing the crosslinkable polymer, and radically or ionically crosslinking the crosslinkable polymer, which is induced thermally or using radiation; and    (5) the crosslinked polymer obtainable by the above method.