NOVELTY - Heterocyclic complex (I) is new.    USE - (I) is useful in electronic devices, preferably in organic electroluminescent devices, organic integrated circuits, -field-effect transistors, -thin film transistors, -light emitting transistors, -solar cells, -optical detectors, --photoreceptors, -field-quench devices, -laser diodes, -plasmon-emitting devices and -light-emitting electrochemical cells; and as a matrix material for fluorescent or phosphorescent emitters and/or in a hole( or electron or exciton) blocking layer and / or in an electron( or hole) transport layer; and in an optical coupling layer (all claimed).    ADVANTAGE - (I): results in significant improvements in the organic electroluminescent device particularly durability, efficiency and operating voltage; also comprises improved oxidation stability in solution and a high temperature stability.    DETAILED DESCRIPTION - Heterocyclic complex of formula (I) is new.    X = C=O, C(R)2, NR, O, S, C=S, C=NR, C=C(R)2, Si(R)2, BR, PR, P(=O)R, SO or SO2;    W1 = CR or N; either    Z = CR or N; or    2Z = an aromatic ring of formula (A);    E = single bond, C(R)2, NR, O, S, C=O, C=S, C=NR, C=C(R)2, Si(R)2, BR, PR, P(=O)R, SO or SO2; either    Y1 = W1 or NR, O or S; or    Ar1+Y1+2C = aryl or heteroaryl with 5-30 aromatic ring atoms, which can be substituted by at least one R;    m, n = 0 or 1;    A = R (when m, n is 0) or aryl or heteroaryl with 5-30 aromatic ring atoms each substituted by R or -CR=CR-, -CR=N- or -N=N- (when m, n is 0 or 1) or aryl or heteroaryl with 5-30 aromatic ring atoms each may be substituted by R (when m, n is 1); either    R = H, D, F, Cl, Br, I, CN, NO2, N(Ar1)2, N(R1)2, C(=O)Ar1, C(=O)R1, P(=O)(Ar1)2, straight chain alkyl, alkoxy or thioalkyl with 1-40C or branched or cyclic alkyl, alkoxy or thioalkyl with 3-40C or alkenyl or alkynyl with 2-40C (each substituted with at least one R1), (where at least one CH2 group can be replaced by R1C=CR1, CC, Si(R1)2, Ge(R1)2, Sn(R1)2, C=O, C=S, Se=C, C=NR1, P(=O)(R1), SO, SO2, NR1, O, S or CONR1 and at least 1 H can be replaced by D, F, Cl, Br, I, CN or NO2) or aromatic or heteroaromatic ring system having 5-80, preferably 5-60 aromatic ring atoms, each substituted with at least one R1 and/or aryloxy or heteroaryloxy group with 5-60 aromatic ring atoms, each substituted with at least one R1; or    optionally two or more adjacent R = monocyclic or polycyclic, aliphatic, aromatic or heteroaromatic ring system (substituted with at least one R1 or R2);    R1 = H, D, F, Cl, Br, I, CN, NO2, N(Ar1)2, N(R2)2, C(=O)Ar, C(=O)R2, P(=O)(Ar1)2, straight chain alkyl, alkoxy or thioalkyl with 1-40C, branched or cyclic alkyl, alkoxy or thioalkyl with 3-40C, or alkenyl or alkynyl with 2-40C (each substituted with at least one R2), (where at least 1 nonadjacent CH2 group can be substituted by R2C=CR2, CC, Si(R2)2, Ge(R2)2, Sn(R2)2, C=O, C=S, Se=C, C=NR2, P(=O)(R2), SO, SO2, NR2, O, S or CONR2, and at least one H can be replaced by D, F, Cl, Br, I, CN or NO2) or aromatic or heteroaromatic ring system having 5-60 aromatic ring atoms each substituted with at least one R2, aryloxy or heteroaryloxy group having 5-60 aromatic ring atoms(substituted with at least one R2); either    R2 = H, D, F, CN, 1-20C aliphatic hydrocarbon, aromatic or heteroaromatic ring system with 5-30 aromatic ring atoms, in which at least one H-atom can be replaced by D, F, Cl, Br, I or CN; or    two or more adjacent R2 = mono- or polycyclic, aliphatic, aromatic or heteroaromatic ring system;    Ar1 = aromatic or heteroaromatic ring system having 5-30 aromatic ring atoms, which can be substituted with at least one non-aromatic R2, thus two Ar1, which bind to N-atom or P-atom, are bridged together through a single bond or a bridge, which is N(R2), C(R2)2 or O; and    p = 0 or 1.    Provided that: Y1 is C, when a group E is bonded to Y1; not more than three W1 are N in a cycle; W1 is C, when a group E is bonded to W1; if m or n is 0, R is bonded to A instead of E; if p is 0, R is bonded to hydrocarbon and/or to W, instead of Z=Z; p is 1, when m, n is 0. INDEPENDENT CLAIMS are also included for:    (1) the preparation of (I); and    (2) an oligomer, dendrimer or polymer containing (I).