NOVELTY - Quinoline complex (I) or (II) is new.    USE - (I) is useful as electron transport layers in electronic devices, preferably organic electroluminescent devices (organic light emitting diodes or polymer light-emitting diodes), organic integrated circuits, organic field-effect transistors, organic thin film transistors, organic light emitting transistors, organic solar cells, organic optical detectors, organic photoreceptors, organic field-quench devices, light-emitting electrochemical cells and organic laser diodes (all claimed).    ADVANTAGE - (I) or (II): exhibits long operating lifetime and high stability against temperature; can be easily processed from the solution; and can be used in organic light emitting diodes without using the separate electron-injection layer.    DETAILED DESCRIPTION - Quinoline complex of formula (I) or (II) is new.    G = substituted heterocyclic compound of formula (Ia), (Ib) or (Ic);    Q = N and CR3;    V1 = O, S, N, CR4 or NR4;    c = covalent single bond;    d = covalent double bond;    R1 = R2-R4, where if R1 is not present, then the quinoline unit is bonded to Y2 at this site;    R2-R4 = 1-40C alkoxy, 1-40C (thio)alkyl (both optionally saturated, optionally branched or cyclic and optionally substituted by at least one R5, and in which at least one nonadjacent CH2 may be replaced by R5C=CR5, CC, Si(R5)2, Ge(R5)2, Sn(R5)2, C=O, C=S, C=Se, C=NR5, P(=O)(R5) , SO, SO2, NR5, O, S or CONR5, and at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), (hetero)aromatic ring with 5-60 aromatic ring atoms (optionally substituted by at least one group R6), (hetero)aryloxy with 5-60 aromatic ring atoms (optionally substituted by at least one group R6), H, D, F, Cl, Br, I, CHO, N(A11)2, C(=O)A11, P(=O)(A11)2, S(=O)A11, S(=O)2A11, CR5=CR5A11, CN, NO2, Si(R5)3, B(OA11)2, B(OR5)2, OSO2R5 and/or OH, where if one of the substituents R2, R3 or R4 is not present in G, then G is bonded to Y1 at this site;    W1 = O, S or NR8;    R8 = R2-R4;    Y1, Y2 = not present (so that the groups that are bonded to Y1 and Y2 are directly linked with each other by covalent single bond), 1-40C alkyl (optionally saturated and optionally branched or cyclic) or (hetero)aromatic ring with 5-60 ring atoms (all optionally substituted by at least one group R6);    A1 = (hetero)aromatic ring with 5-60 aromatic ring atoms (optionally substituted by at least one group R9);    R9 = R2-R4; either    A11 = (hetero)aromatic ring with 5-30 aromatic ring atoms (optionally substituted by at least one group R7); or    2A11+N or 2A11+P = B(R7), C(R7)2, Si(R7)2, C=O, C=NR7, C=C(R7)2, O, S, S=O, SO2, N(R7), P(R7) or P(=O)R7;    R5 = 1-20C alkyl (optionally saturated and optionally branched or cyclic, in which at least one H may be replaced by D or F), (hetero)aromatic ring with 5-20 ring atoms (in which at least one H may be replaced by F) (all optionally substituted by at least one group R6), H or D;    R6 = 1-40C alkoxy, 1-40C (thio)alkyl (both optionally saturated, optionally branched or cyclic and optionally substituted by at least one group R7 and in which at least one non-adjacent CH2 may be replaced by R7C=CR7, CC, Si(R7)2, Ge(R7)2, Sn(R7)2, C=O, C=S, C=Se, C=NR7, P(=O)(R7), SO, SO2, NR7, O, S or CONR7 and at least one H may be replaced by D, F, Cl, Br, I, CN or NO2), H, D, F, Cl, Br, I, CHO, N(A11)2, C(=O)A11, P(=O)(A11)2, S(=O)A11, S(=O)2A11, CR7=CR7A11, CN, NO2, Si(R7)3, B(OA11)2, B(OR7)2, OSO2R7 or OH;    R7 = 1-20C alkyl (optionally saturated and optionally branched or cyclic, in which at least one H may be replaced by F or D), (hetero)aromatic ring with 5-20 ring atoms (in which at least one H may be replaced by D or F), H or D;    M = mono-, di-, tri- or tetravalent metal;    L1 = mono- or bidentate ligand;    m = 0-4, where at least one m is greater than 0;    n = 1-4;    r = 1-4;    k = 0-6; and    l = 0-6.    Provided that when V1 is O, S or NR4, then R3 represents a non-bonding electron pair.    INDEPENDENT CLAIMS are also included for:    (1) an oligomer or a polymer containing a structural unit of formula (-L-A1((Y1-G)m)-L-M((L1)a)-) (XIII) or (XIV)-(XXI);    (2) substituted quinoline compound of formula (XXII);    (3) preparing (I) or (II); and    (4) a formulation comprising at least one compound (I) or (II) and at least one solvent.    L = bidentate ligand of formula (Ip);    a = 0-2;    b = 0 or 1; and    m = undefined.