TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): The organic compounds (I)-(III) are prepared by following steps: at -10 to 40 degrees C, adding bromo ketone Ar1-C(O)-CH(R2)Br and pyridine into a first solvent, to obtain bromopyridinium; in the atmosphere of inert gases, adding the bromopyridinium, aromatic diketone, aromatic aldehyde and catalysis amount ammonium salt, into second solvent and then refluxing. The organic compounds (IV)-(VI) are prepared by following steps: at -10 to 40 degrees C, adding bromo ketone Ar2-C(O)CH(R5)-Br and pyridine into a third solvent, then bromopyridinium is obtained; in the atmosphere of inert gases, adding the bromopyridinium, aromatic dialdehyde, aromatic ketone, and catalysis amount ammonium salt, into a fourth solvent and then refluxing. Preferred Compound: The organic compound is one of multi-aryl substituted pyridine derivatives as given in the specification e.g. pyridine derivatives of formulae (Ia) and (IIa).R3,R3',R4,R4'=1-20C alkyl, 3-20C cyclic alkyl or 1-20C alkoxy (all optionally substituted), H, 7-50C aralkyl, 6-50C aryl, 6-50C aryloxy or 5-50C heterocyclic aryl. SPECIFIC COMPOUNDS - 48 Compounds are disclosed as the organic compounds (C1) e.g. 1,4-bis(4,6-diphenyl-5-(trifluoromethyl)pyridin-2-yl)benzene (IA); 1,4-bis(6-phenyl-4-p-tolyl-5-(trifluoromethyl)pyridin-2-yl)benzene; 6,6'-(1,4-phenylene)bis(2,4-diphenylnicotinonitrile); 6,6'-(1,4-phenylene) bis(4-(4-tert-butylphenyl)-2-phenylnicotinonitrile); and diethyl 6,6'-(1,4-phenylene) bis(2-phenyl-4-p-tolylnicotinate).    EXAMPLE - 2-Bromo-3,3,3-trifluoro-1-phenylpropan-1-one and pyridine (1:1 in molar ratio) were stirred at the room temperature of 25 degrees C for 10 hours in ethanol (2 times (weight) of the total amount of 2-bromo-3,3,3-trifluoro-1-phenylpropan-1-one and pyridine), then filtrated, and the resulted solids were washed with water, to obtain pyridinium bromide. The resulted pyridinium bromide, 1,4-diacetylbenzene and benzaldehyde (2:1:2 in molar ratio) were added into a three-necked flask and then acetic acid (5 times (weight) of the total amount of the resulted pyridinium bromide, 1,4-diacetylbenzene and benzaldehyde) and catalysis amount ammonium acetate (10 molar % of the resulted pyridinium bromide) (10 molar % of the resulted pyridinium bromide) were added. The mixtures were refluxed for 24 hours, to give 1,4-bis(4,6-diphenyl-5-(trifluoromethyl)pyridin-2-yl)benzene (yield 50%). An organic semiconductor device using 1,4-bis(4,6-diphenyl-5-(trifluoromethyl)pyridin-2-yl)benzene had turn-on voltage 4.2V, maximal brightness 19800 cd/m2 (12V); and current efficiency 5.5 cd/A.