NOVELTY - An electroluminescent device comprises a first electrode; second electrode; and at least one organic layer interposed between the first and second electrodes; where the organic layer comprises divalent or trivalent metal complex as host material.    USE - As organic solar cell and organic electroluminescent device (OLED) (claimed).    ADVANTAGE - The electroluminescence devices (EL devices) are self-luminescent display devices showing the advantage of wide angle of view, excellent contrast and rapid response rate, as compared to liquid crystal displays (LCD's); exhibit excellent luminous efficiency, high color purity, low operation voltage and good operation life. The device lowers the power consumption of the OLED, with lowering the operation voltage by 0.9-1.7 V.    DETAILED DESCRIPTION - An electroluminescent device comprises a first electrode; second electrode; and at least one organic layer interposed between the first and second electrodes; where the organic layer comprises divalent or trivalent metal complex as host material of formula L1L2M(Q)y (I).    L1 and L2=ligands selected from group of formulae (i) or (ii) (preferably selected from 22 groups as given in the specification e.g. group of formula (iii)-(v));    M=divalent or trivalent metal;    y=0 or 1;    Q=6-60C aryloxy or tri-6-60C arylsilyl (both optionally substituted by 1-60C alkyl or 6-60C aryl);    X=O, S or Se;    ring A and ring B'=5- or 6-membered heteroaromatic ring, or 5- or 6-membered heteroaromatic ring with 6-60C aromatic ring fused (both optionally substituted by at least one G1);or    ring A+R1=fused ring;    G1=1-60C alkyl, halo, 1-60C alkyl (substituted by halo), 6-60C aryl, 4-60C heteroaryl, tri-1-30C alkylsilyl, di-1-30C alkyl-6-30C arylsilyl, tri-6-30C arylsilyl, di-1-30C alkylamino or di-6-30C arylamino;    R11, R12 and R21-R23=H or G1;    R1-R7=H, 1-60C alkyl, halo, 1-60C alkyl (substituted by halo), tri-1-30C alkylsilyl, di-1-30C alkyl-6-30C arylsilyl, tri-6-30C arylsilyl, 6-60C aryl, 4-60C heteroaryl, di-1-30C alkylamino or di-6-30C arylamino;    G2=1-60C alkyl, halo, cyano, 1-60C alkyl (substituted by halo), 3-60C cycloalkyl, 1-30C alkoxy, 6-60C aryl, 4-60C heteroaryl, tri-1-30C alkylsilyl, di-1-30C alkyl-6-30C arylsilyl, tri-6-30C arylsilyl, di-1-30C alkylamino or di-6-30C arylamino.    Each of R1-R7 optionally linked to an adjacent substituent via alkylene or alkenylene to form a fused ring. The (hetero)aryl to be substituted on ring A or ring B', or the (hetero)aryl of R1-R7, R11, R12 and R21-R23, or the fused ring formed by linkage to an adjacent substituent via alkylene or alkenylene are optionally further substituted by at least one G2. Provided that when M is a divalent metal, then y is 0; and when M is a trivalent metal, then y is 1. An INDEPENDENT CLAIM is included for an organic solar cell comprising the organic electroluminescent compound (I).