NOVELTY - A (pyrimidinylphenyl)pyrimidine derivative (I, II or III), (pyridinylphenyl)pyrimidine derivative (IV, V, VI or VII), (pyridinylphenyl)triazine derivative (VIII or IX), or (pyrimidinylphenyl)triazine derivative (X or XI) is new.    USE - New (pyrimidinylphenyl)pyrimidine derivative, (pyridinylphenyl)pyrimidine derivative, (pyridinylphenyl)triazine derivative, or (pyrimidinylphenyl)triazine derivative is used as charge transporting material, phosphorescent host material, fluorescent host material, or fluorescent blue dopant in organic photoelectric device of display device (all claimed). Uses include but are not limited to organic light-emitting device, organic solar cell, organic transistor, organic photoconducting drum, and organic memory device.    ADVANTAGE - The new compound provides longer-lasting organic photoelectric devices having excellent light-emitting efficiency even at low drive voltages.    DETAILED DESCRIPTION - A (pyrimidinylphenyl)pyrimidine derivative of formula (I, II or III), (pyridinylphenyl)pyrimidine derivative of formula (IV, V, VI or VII), (pyridinylphenyl)triazine derivative of formula (VIII or IX), or (pyrimidinylphenyl)triazine derivative of formula (X or XI) is new.    R1=H, or 1-30C alkyl, 6-30C aryl, 3-30C heteroaryl, 6-30C arylamino, carbazolyl, or fluorenyl (all optionally substituted);    Ar1-Ar4=6-30C aryl, 6-30C arylene, 3-30C heteroaryl, 3-30C heteroarylene, 6-30C arylamino, carbazolyl, or fluorenyl (all optionally substituted);    Ar5-Ar8=6-30C aryl, 3-30C heteroaryl, 6-30C arylamino, carbazolyl, or fluorenyl (all optionally substituted);    a,b,c,d=0-2;and    e=0-3.    (i) a, b, c and d are not 0 simultaneously; (ii) The carbon number of Ar1-Ar4 is 7-30; (iii) All aryl are chosen from phenyl, biphenyl, terphenyl, stilbenyl, naphthyl, anthracenyl, phenanthrenyl, pyrenyl and perylenyl; (iv) All arylene are chosen from phenylene, biphenylene, terphenylene, stilbenylene, naphthylene, anthracenylene, phenanthrenylene, pyrenylene and perylenylene; (v) All heteroaryl are chosen from thiophenyl, furanyl, pyrrolyl, imidazolyl, thiazolyl, oxazolyl, oxadiazolyl, triazolyl, pyridinyl, pyridazinyl, quinolinyl, isoquinolinyl, acridinyl, imidazopyridinyl, imidazopyrimidinyl and benzoquinolinyl; and (vi) All heteroarylene are chosen from thiophenylene, furanylene, pyrrolylene, imidazolylene, thiazolylene, oxazolylene, oxadiazolylene, triazolylene, pyridinylene, pyridazinylene, quinolinylene, isoquinolinylene, acridinylene, imidazopyridinylene, imidazopyrimidinylene and benzoquinolinylene. An INDEPENDENT CLAIM is included for organic photoelectric device (500) consisting of an organic thin-film layer (105) containing the new compound, interposed between an anode (120) and a cathode (110).    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional of the organic photoelectric device.    Organic thin-film layer (105)    Cathode (110)    Anode (120)    Light-emitting layer (130)    Hole transport layer (140)    Electron transport layer (150)    Electron injection layer (160)    Hole implant layer (170)    Organic photoelectric device (500)