TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Film: The functional organic film is coupled to the substrate through siloxane coupling. The organic residue is a residue of pi-electron conjugated system whose 3-10 units (A) are coupled in the form of straight line. The units (A) are derived from monocyclic aromatic hydrocarbon, fused polycyclic hydrocarbon, monocyclic heterocyclic-compound, condensation heterocyclic compound, alkene, alkadiene or alkatriene, preferably the unit (A) is phenylene, thiophene diyl or ethylene. The thin film contains one or more monomolecular film originating from silicon compound. The film thickness of the monomolecular film is 1-12 nm. The functional organic thin film has molecular crystallinity and shows electroconductivity along vertical direction with respect to substrate surface. The film has electrical anisotropy which shows semiconductivity along the substrate surface direction.Preferred Film Formation: A functional organic thin film consisting of monomolecular film (II) containing a silicon compound formed on monomolecular film (I). The monomolecular film (II) contains compound of formula K2-R'-K3.R' = organic residue formed by coupling several pi-electron conjugated system;K2,K3 = functional group or hydrogen atomK2 and K3 are not hydrogen atoms simultaneously. The monomolecular film (I) is formed by chemical absorption process using the silicon compound.Preferred Transistor: The gate insulation film and organic thin film are coupled by siloxane coupling and are not coupled with R groups adjacent to substrate surface. The transistor is formed by coupling linear units (A) together.Preferred Compound: The pi-electron conjugated system molecule-containing silicon compound has formula R1-SiX1X2X3.R1 = organic residue of pi-electron system originating from heterocyclic compound of monocyclic aromatic hydrocarbon or monocyclic ring formed by coupling 3-10 units, and having functional group at the terminal;andX1-X3 = halogen atom or lower alkoxy groupR1 contains vinylene group. The heterocyclic compound of monocyclic aromatic hydrocarbon and monocyclic ring is benzene or thiophene.Preferred Method: The pi-electron conjugated system molecule-containing silicon compound is obtained by performing Grignard reaction of R1-MgX and Y-SiX1X2X3.R1,Y,X1-X3 = same as defined above;andX = H, halogen atom or lower alkoxy group.The group R halogenates predetermined joint position of raw material compound selected from heterocyclic compound of monocyclic aromatic hydrocarbon and mono-cyclic ring, by repeating the Grignard reaction once or more. The group R is originated from thiophene and halogenates the predetermined joint position of thiophene. The silicon compound is obtained by combining the thiophene of a predetermined number, by repeating the reaction of halogenated thiophenes in the presence of NCS or POC13 or by repeating cyclization process, once or more. By reacting the obtained halogenated thiophene and a divinyl sulfone, 1,4-diketone compound in which the thiophene is coupled with both sides of succinyl group, is obtained. Group R halogenates methyl group of the raw material compound. The pentavalent phosphorus compound substituted the halogen. The monocyclic aromatic hydrocarbon which has an aldehyde group in a predetermined joint position, and a mono-cyclic ring are made to react once or more. Preferred Definitions:    X1-X3 = halogen atom or lower alkoxy group.    EXAMPLE - 1.5 mol of terphenyl was dissolved in carbon tetrachloride. Nitrile-butadiene-styrene and aluminum boron nitride were added and stirred for 3 hours. Filtration was performed to obtain a promoter phenyl. 0.5 mol of the obtained promoter phenyl was dropped into a solution containing magnesium (0.5 mol) dissolved in 300 ml of tetrahydrofuran, at 50-60degreesC. Ripening process was performed at 65degreesC, to obtain a Grignard reagent. 1 mol of tetrachlorosilane and 300 ml of toluene were added into a flask and cooled in ice. Grignard reagent was added at 20degreesC or less. Maturation was performed at 30degreesC after dripping completion. The obtained reaction solution was filtered and magnesium chloride was removed. Stripping of toluene and unreacted tetrafluorosilane from the filtrate, was performed. The solution was distilled, to obtain terphenyl trichlorosilane of yield 50%. The structure of the compound was confirmed by infrared absorption spectrum and nuclear magnetic resonance spectrum. Using the obtained compound, an organic thin film was formed. The obtained film had electrical conductivity of 10-4 S/cm with respect to the substrate orthogonal direction. Using the obtained film, an organic thin-film transistor having favorable electrical, optical and electrochemical properties, was obtained.