TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclosed): Diarylamine derivative of formula (A) is coupled with halogenated aryl derivative of formula (B) in presence of base such as sodium hydride and sodium butoxide, and catalyst such as 2-(dicyclohexyl phosphino)biphenyl, tris(dibenzylidene acetone)dipalladium and solvent such as xylene, at 100-150degrees C for 1-10 hours, to obtain triarylamine derivative of formula (1).R1-R11=same as defined above;andX1=halogen.Preferred Compound: At least 1 phenyl group coupled with nitrogen atom in the triarylamine derivative, has at least 1 substituent substituted in ortho-position with respect to nitrogen atom.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: A photoreceptor layer (11) including binder resin and charge-transport agent including triarylamine derivative is provided on the electroconductive base, to form an electrophotographic photoreceptor (1). SPECIFIC COMPOUNDS - 17 triarylamine derivatives are disclosed such as (3,4-bis-(diphenyl-hydrazonomethyl)-phenyl)-(4-chloro-phenyl)-phenyl-amine of formula (a), (3-(diphenyl-hydrazonomethyl)-4-(naphthalene-2-yl-phenyl-hydrazonomethyl)-phenyl)-phenyl-o-tolyl-amine, (3,4-bis-(diphenyl-hydrazonomethyl)-phenyl)-(4-isopropyl-phenyl)-o-tolyl-amine, (4,5-bis-(diphenyl-hydrazonomethyl)-2-methyl-phenyl)-naphthalene-2-yl-phenyl-amine and (4-((4-chloro-phenyl)-phenyl-hydrazonomethyl)-3-(diphenyl-hydrazonomethyl)-phenyl)-phenyl-(2,4,6-trimethyl-phenyl)-amine (disclosed).    EXAMPLE - 4-chlorophthalaldehyde (in g) (16.3), diphenylamine hydrochloride of formula (C) (4), zinc chloride (2.64) and toluene (200 ml) were added into a flask, refluxed for 3 hours, cooled to room temperature, and separated organic layer was washed with ion-exchange water. Anhydrous sodium sulfate and activated clay were added to the organic layer, toluene was distilled and purified, to obtain white crystals of hydrazone compound of formula (D) (15.6) in yield of 80.6%. The obtained hydrazone compound (14), 2-(dicyclohexyl phosphino)biphenyl (24.5 mg), tris(dibenzylidene acetone)dipalladium (31.9 mg), t-butoxy sodium (2.01), ortho toluidine (2.99) and ortho-xylene (100 ml) were reacted at 120degrees C for 3 hours, cooled to room temperature and separated organic layer was washed with ion-exchange water. Anhydrous sodium sulfate and activated clay were added to organic layer, dried, xylene was distilled, and purified to obtain pale-yellow crystals of (3,4-bis(diphenyl-hydrazonomethyl)-phenyl)-o-tolyl amine (12.2) in yield of 76.5%. The obtained (3,4-bis(diphenyl-hydrazonomethyl)-phenyl)-o-tolyl amine (10.5), 2-(dicyclohexyl phosphino)biphenyl (16 mg), tris(dibenzylidene acetone)dipalladium (21 mg), t-butoxy sodium (1.33), 1-chloro 4-methylbenzene (2.33) and ortho xylene (100 ml) were reacted at 120degrees C for 3 hours, cooled to room temperature and separated organic layer was washed with ion-exchange water. Anhydrous sodium sulfate and activated clay were then added to the organic layer, dried, xylene was distilled and purified to obtain yellow crystals of (3,4-bis-(diphenyl-hydrazonomethyl)-phenyl)-o-tolyl-p-tolyl-amine (9.55) in yield of 78.4%. The obtained (3,4-bis-(diphenyl-hydrazonomethyl)-phenyl)-o-tolyl-p-tolyl-amine of formula (I) had excellent sensitivity, solubility with respect to solvent, and compatibility with binder resin. An electrophotographic photoreceptor having monolayer-type photosensitive layer including (3,4-bis-(diphenyl-hydrazonomethyl)-phenyl)-o-tolyl-p-tolyl-amine, of formula (I) was formed. The photoreceptor had initial-stage surface potential (Vo) of 698, and rest potential (Vr) of 136.