NOVELTY - Substituted fused heteroaryl compounds (I) are new.    USE - (I) are useful: in an optoelectronic device including , an organic light emitting diode, an organic solar cell, an organic transistor, an organic photo-conductor drum or an organic memory device; as a hole transport material or a hole injection material for an organic light emitting diode; as a phosphorescent or fluorescent host material in an emission layer; an organic light emitting diode, which is useful in a display device (all claimed); and a fluorescent blue dopant material in an emission layer.    ADVANTAGE - (I) exhibits excellent hole or electron transporting property, high film stability, good thermal stability and good triplet exciton energy (of greater than or equal to 2 eV), and provides an optoelectronic device, which exhibits excellent life-span, efficiency, electrochemical stability and thermal stability, and has high luminous efficiency at a low driving voltage.    DETAILED DESCRIPTION - Substituted fused heteroaryl compounds of formula (I) are new.    R1-R16 = 1-20C alkyl, 6-30C aryl, 2-30C heteroaryl, 1-20C alkoxy, 6-20C aryloxy, 3-40C silyloxy, 1-20C acyl, 2-20C alkoxycarbonyl, 2-20C acyloxy, 2-20C acylamino, 2-20C alkoxycarbonyl amino, 7-20C aryloxycarbonyl amino, 1-20C sulfamoyl amino, 1-20C sulfonyl, 1-20C alkylthiol, 6-20C arylthiol,1-20C heterocyclothiol, 1-20C ureide, 3-40C silyl, 1-20C amine (all optionally substituted), H, D, halo, CN, OH, NH2, NO2, carboxy or ferrocenyl;    X = NR17, O, S or SO2;    R17 = 1-20C alkyl, 6-30C aryl or 2-30C heteroaryl (all optionally substituted);    Y1 = O, S or SO2;    Ar1, Ar2 = 6-30C aryl or 2-30C heteroaryl (both optionally substituted);    n = 1-4;    m = 0-4; and    Ar3 = 6-30C aryl or 2-30C heteroaryl (both optionally substituted).    Provided that: Ar3 is not carbazolyl, dibenzofuranyl or dibenzothiophenyl (all optionally substituted); when X is NR17, then Ar3 is not a fluorenyl; at least one of R1-R8 represents a bond with Ar1; at least one of R9-R16 represents a bond with Ar2; at least one of R1-R8 is optionally bound to Ar1 through a sigma bond; and at least one of R9-R16 is optionally bound to Ar2 through a sigma bond. An INDEPENDENT CLAIM is also included for an organic light emitting diode including an anode (120), a cathode (110), and at least one organic thin film between the anode and the cathode is provided, and at least one of the organic thin films (105), which comprises (I).    DESCRIPTION OF DRAWING(S) - The figure shows a cross-sectional view of organic light emitting diodes including (I).    Organic photoelectric device (100)    Organic thin layer (105)    Cathode (110)    Anode (120)    Emission layer (130)