NOVELTY - New transition metal complexes (I) have 1-3 molecules of bidentate polycyclic ligand (L) and 0-2 molecules of each of 2 monoanionic, bidentate chelating ligands, where L has a 1-ring and condensed 2-ring (un)saturated or aromatic homo- or heterocycle linked to the metal, one by carbon atom and other by heteroatom with non-bonding electron pair, whilst the single ring is linked directly to one ring and (in)directly to other ring of 2-ring system.    USE - Compounds (I) and the polymers and dendrimers are used in electronic devices (claimed). These devices, especially an organic light-emitting diode (OLED), organic integrated circuit (O-IC), organic field-effect transistor (O-FET), organic thin-film transistor (O-TFT), organic solar cell (O-SC) or organic laser diode (O-laser), claimed per se. The materials and mixtures are useful in organic electronic devices such as electroluminescent elements and displays based on these. (II) are intermediates for (I) synthesis.    ADVANTAGE - Compounds in which a phenyl ring is linked to an isoquinoline ring by a monoatomic bridge have excellent properties as triplet emitter in organic light-emitting diodes (OLEDs). They can be prepared with good reproducibility in reliable high purity, without variation between charges, which makes industrial production of the electroluminescent devices more efficient. The compounds have good solubility in organic solvents, which facilitates purification and processing by coating or printing techniques; better oxidation stability than usual, which facilitates purification and handling; and high temperature stability, generally allowing vaporization in high vacuum without decomposition.    DETAILED DESCRIPTION - New transition metal complexes (I) are of formula (1): M(L)n(L')m(L)o (1);    M(L)n = a group of formula (2);    M = a transition metal ion;    Y = a specified bridge or single bond;    D = carbon in one case, heteroatom with non-bonding electron pair in other;    E = C or in one case N;    Cy1, Cy2, Cy3 = (un)saturated or aromatic homo- or heterocycles;    n = 1, 2 or 3;    L', L = monoanionic, bidentate chelating ligands;    m, o = 0, 1 or 2.    The full definitions are given in the DEFINITIONS (Full Definitions) Field. INDEPENDENT CLAIMS are also included for the following:    (1) new polycyclic compounds (II) corresponding to some ligands L;    (2) preparation of (I);    (3) preparation of (II);    (4) (partly) conjugated or unconjugated polymers or dendrimers containing (I);    (5) electronic devices containing compound(s) (I) and/or the polymer(s) or dendrimer(s).