NOVELTY - An aromatic compound having fluorene-containing structure (I), aromatic structure (II) or (III) or nitrogen-containing structure (IV), is new.    USE - New aromatic compound is used for hole transport material and hole injection material for organic optoelectronic device e.g. organic photoelectric device, organic light-emitting diode, organic solar cell, organic transistor, organic photoconductor drum and organic memory device (all claimed). Uses include but are not limited to electrode material, discoloring material, photoswitch, sensor, module, waveguide, light-absorbing agent and dielectric material.    ADVANTAGE - The aromatic compound has high hole or electron transporting property and high triplet excitation energy. The organic light-emitting diode containing the aromatic compound has excellent electrochemical stability, thermal stability, durability and luminous efficiency, and low drive voltage.    DETAILED DESCRIPTION - An aromatic compound having fluorene-containing structure of formula (I), aromatic structure of formula (II) or (III) or nitrogen-containing structure of formula: casterisk-(L)n-N(-Ar2)-Ar1 (IV), is new.    X=O, S, O=S=O, P=O, or C=O;    Y'=CR'R" or NR';    R',R",R1,R2=H, deuterium, halo, cyano, hydroxy, amino, nitro, carboxy, ferrocenyl, or 1-20C amino, 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 alkoxycarbonylamino, 7-20C aryloxycarbonylamino, 1-20C sulfamoylamino, 1-20C sulfonyl, 1-20C alkylthio, 6-20C arylthio, 1-20C heterocyclylthio, 1-20C ureido or 3-40C silyl (all optionally substituted);    Ar1,Ar2=6-30 aryl or 2-30C heteroaryl (both optionally substituted);    L=single bond, or 2-6C alkenylene, 2-6C alkynylene, 6-30 arylene, heteroarylene (all optionally substituted);    n=0 or 1;and    or two adjacent asterisk of fluorene-containing structure (I)+two adjacent asterisk of aromatic structure (II) or (III)=fused ring.    (i) aasterisk of fluorene-containing structure (I) or basterisk of aromatic structure (II) or (III) are linked to casterisk of nitrogen-containing structure through ( sigma )-bonding, and remaining aasterisk or basterisk which is not linked to casterisk are H. An INDEPENDENT CLAIM is included for organic light-emitting diode (100), which has an anode (120), a cathode (110) and an organic thin layer (105) containing aromatic compound interposed between anode and cathode.    DESCRIPTION OF DRAWING(S) - The drawing shows the cross-sectional view of the organic light-emitting diode.    Organic light-emitting diode (100)    Organic thin layer (105)    Cathode (110)    Anode (120)    Emission layer (130)