NOVELTY - Polymer containing an aromatic ketone containing structural unit in the side chain, is new.    USE - The polymer or the mixture or the formulation or the compound (Ia) is useful in electronic devices, preferably in organic electroluminescent devices, which are organic and/or polymeric organic electroluminescent devices (OLED, PLED), organic integrated circuits (O-IC), organic field-effect transistors (OFET), organic thin film transistors (OTFT), organic solar cells (O-SC), organic laser diodes (O-lasers), organic photo-voltaic elements (OPV) or devices or organic photoreceptors (OPCs), preferably a polymeric organic electroluminescent device (PLED) (all claimed).    ADVANTAGE - The organic electroluminescent device produced from the polymer material shows good power efficiency and stable for longtime.    DETAILED DESCRIPTION - Polymer containing an aromatic ketone containing structural unit of formula (S1-L-Ar1-(Q)m-(Ar1-(L-Ar2)l)s) (I) in the side chain, is new.    S1 = connection to the backbone of the polymer;    L = a covalent single bond or a straight chain 1-20C alkylene or a branched or a cyclic 3-20C alkylene group, respectively substituted by at least one R1, where at least one non adjacent CH2-group can be replaced by Y1 and at least one H atom can be replaced by Z1;    Y1 = R2C=CR2, CC, Si(R2)2, Ge(R2)2, Sn(R2)2, C=O, C=S, C=Se, C=NR2, P(=O) (R2), SO, SO2, NR2, O, S or CONR2;    Z1 = F, Cl, Br, I, CN or NO2, preferably a covalent single bond;    Ar1 = a bivalent, mono or polycyclic, aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which can be substituted with at least one R1;    Ar2 = mono or polycyclic, aromatic or heteroaromatic ring system with 5 to 60 aromatic ring atoms, which can be substituted by R1;    Q = a bivalent unit, which is either 1,3,5-triazine or -X(=O)-;    m = 1-3, preferably 1;    l = 0-3;    s = 1-2;    R1 = D, F, Cl, Br, I, N(Ar3)2, CN, NO2, Si(R2)3, B(OR2)2, C(= O)Ar3, P(=O) (Ar3)2, S(=O)Ar3, S (=O)2Ar3, -CR2=CR2(Ar3), tosylate, triflate, OSO2R2, straight chain alkyl, alkoxy or thioalkoxy with 1-40C or a branched or cyclic alkyl, alkoxy or a thio-alkoxy with 3-40C, respectively substituted with at least one R2, where at least one non adjacent CH2-group can be replaced by Y1 and at least one H atom can be replaced by Z1;    X = C, P(Ar4), S or SO, consists, preferably C or P (Ph);    R2 = straight chain alkyl with 1-20C or a branched or a cyclic alkyl with 3-20C, or mono or polycyclic, aromatic or heteroaromatic ring system with 5-20 aromatic ring atoms, which is respectively substituted by at least one R3, where at least one non adjacent CH2 groups can be replaced by NH, O or S and at least one H-atom can be replaced by F;    R3 = a straight chain alkyl with 1-20C or a branched or a cyclic alkyl with 3-20C, where at least one non adjacent CH2 group can be replaced by NH, O or S and at least one H-atom can be replaced by F;    Ar3, Ar4 = mono or polycyclic, aromatic or heteroaromatic ring system with 5-60 aromatic ring atoms, which can be substituted with at least one R3;    Z = a bivalent group -(CR42)q-;    q = 1-5; and    R4 = a straight chain alkyl group with 1-20C or a branched or a cyclic alkyl group with 3-20C, where at least one non adjacent CH2 groups can be replaced by NH, O or S and at least one H-atom can be replaced by F.    Provided that s is 1 in case of Q is -X(=O)- and is 1 or 2 in case of Q is 1,3,5-triazine. Where two or more neighboring substituents R1/R2/R3 can be linked with each other over a covalent single bond or a bivalent group of Z. INDEPENDENT CLAIMS are also included for:    (1) a mixture of the polymer(s) with further polymers, oligomers, dendritic or low molecular substances;    (2) a formulation comprising the polymer(s) or the mixture in at least one solvent; and    (3) a polymer compound of formula (P-L-Ar1-(Q)m-(Ar1-(L-Ar2)l)s) (Ia).