TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of the diphenyl amine derivative (I) involves: (a) reacting amine compound of formula (III) with phenyl compound of formula (IVa) to obtain phenyl compound of formula (V); and (b) reacting the compound (V) with a phenyl compound of formula (IVb) to obtain derivative (I). In steps (a) and/or (b), a palladium compound is used as a catalyst. The steps (a) and/or (b), are carried out in the presence of a base.X1 and X2=halo.Preferred Components: The photoconductor layer is a monolayer type photoconductor layer and the content of the diphenyl amine derivative is of 20-500 parts by weight with respect to 100 parts by weight of the binding resin of the photoconductor layer. The photoconductor layer is a multilayer type photoconductor layer and the content of the diphenyl amine derivative is of 10-500 parts by weight with respect to 100 parts by weight of the binding resin of the charge transfer layer included in the photoconductor layer. Preferred Definitions:    R1-R3, R6, R7-R9 and R12=H.    SPECIFIC COMPOUNDS - 12 Compounds are specifically disclosed as (I) e.g. bis-(4-((E)-styryl)-phenyl)-(5,6,7,8-tetrahydro-naphthalen-1-yl)-amine of formula (Ia), (5,6,7,8-tetrahydro-naphthalen-1-yl)-bis-(4-((E)-2-p-tolyl-vinyl)-phenyl)-amine, bis-(4-((1E,3E)-4-phenyl-buta-1,3-dienyl)-phenyl)-(5,6,7,8-tetrahydro-naphthalen-1-yl)-amine, bis-(4-((1E,3E)-4-phenyl-buta-1,3-dienyl)-phenyl)-(5,6,7,8-tetrahydro-naphthalen-2-yl)-amine, (4-((1E,3E)-4-phenyl-buta-1,3-dienyl)-phenyl)-(4-((E)-styryl)-phenyl)-(5,6,7,8-tetrahydro-naphthalen-1-yl)-amine.    EXAMPLE - 1-Chloro-4-((E)-styryl)-benzene (7.3 g), (2-biphenyl) dicyclohexyl phosphine (0.07 g), tris (dibendilidene acetone) dipalladium (O) (0.1 g), sodium-tert-butoxide (5 g), and 5,6,7,8-tetrahydro-naphthalen-1-ylamine (2.57 g) placed in a flask, ortho-xylene(500 ml) was added, and the argon gas substitution was carried out so as to be agitated for 3 hours while being heated at 120 degrees C. After cooling down to the room temperature, the organic layer was washed with ion exchange water for 3 times, and a drying and adsorption process was applied to the organic layer using a sodium sulfide anhydride and active white clay, and xylene was removed under reduced pressure. After worked up, bis-(4-((E)-styryl)-phenyl)-(5,6,7,8-tetrahydro-naphthalen-1-yl)-amine (Ia) (7.4 g, yield 86%) was obtained. The solubility of the obtained compound (Ia) was evaluated. The sample was added to a tetrahydrofuran so as to have a 25% by mass concentration for confirming the solubility by the visual observation for evaluation. The solution was transparent, showing good solubility. A monolayer type photoconductor layer application liquid was prepared by mixing and dispersing X type non metal phthalocyanine as the charge generating agent (5 parts by weight (pbw)), the compound (Ia) (80 pbw) as the hole transfer agent, 3',5'-di-tert-butyl-3,5-dimethyl-bicyclohexylidene-2,5,2',5'-tetraene-4,4'-dione as the electron transfer agent (50 pbw), and siloxane component containing polycarbonate resin as the binding resin (100 pbw) in a tetrahydrofuran (800 pbw) as the solvent for 50 hours. Then, by applying the application liquid onto a conductive base member including an aluminum bare pipe by the dip coat method, and hot air drying at 100 degrees C for 30 minutes, a 25 microns film thickness photoconductor layer was formed so as to obtain a monolayer type photoconductor. The surface potential of monolayer type photoconductor was measured and found to be 125 V. The photoconductor layer surface of the monolayer type photoconductor was observed for evaluation and crystallization was not observed, thus showing good photoconductor external appearance.