TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: The electron withdrawing group substituted N-alkyl indole derivative trimer of formula (3) is obtained by reacting N-alkyl group substituted indole derivative of formula (2), oxidizing agent(s) and organic solvent(s).R16 = 1-24C alkyl group; andR17-R20 = R4 including amide group.Preferred Oxidizing Agent: The oxidizing agents are anhydrous ferric chloride, anhydrous ferric chloride hexa hydrate, ferric nitrate hexa hydrate, ferric sulfate n-hydrate, ferric ammonium sulfate dodecahydrate, perchloric acid ferric n-hydrate, cupric chloride, cupric tetra fluoroboric acid, ozone and/or ammonium persulfate. The oxidizing agent is dissolved in water, and then used in the reaction mixture.Preferred Solvent: The organic solvent is acetone, acetonitrile, 1,4-dioxane, gamma-butyl lactone, N,N-dimethylformamide and/or propylene carbonate.Preferred Properties: The particle size of the electron withdrawing group substituted N-alkyl indole derivative trimer is 0.1-50 mum. The interlayer spacing of the electron withdrawing group substituted N-alkyl indole derivative trimer in a laminated structure, is 0.1-0.6 nm. Preferred Definitions:    electron-attractive group of formula (1) = carboxylic acid, sulfonic acid, cyano, aldehyde, nitro, fluoro, amide, acyl and/or cyano vinyl group; and    Xa- = chloride ion, bromine ion, iodine ion, fluorine ion, nitrate ion, sulfate ion, hydrogen sulfate ion, phosphate ion, tetrafluoro boric-acid ion, hexafluoro-phosphate ion, perchlorate ion, thiocyanic acid ion, acetic acid ion, propionic acid ion, methane sulfonic acid ion, p-toluenesulfonic acid ion, trifluoroacetic acid ion and/or trifluoromethane sulfonic acid ion.    EXAMPLE - N-ethyl indole-5-carbonitryl (in g) (1.70) was dissolved in acetonitrile (10 ml) to obtain indole-5-carbonitryl solution. The obtained solution was covered and mixed with oxidizing agent solution obtained by stirring anhydrous ferric chloride (16.2) and water for 10 minutes. The reaction solution was stirred at 60 degrees C for 10 hours, and filtered. The filtrate was washed using methanol, and dried to obtain green di indolo(5,6,11-triethyl-dihydro-5H) (2,3-a:2', 3'-c) carbazole-2.9,14-tricarbonitryl and N-triethyl indole-5-carbonitryl trimer (1.45). The trimer obtained with an yield of 85% was press-molded and cut in a shape of thickness 1 mm and diameter 10 mm. The interlayer spacing of the trimer in the molded product was found to be 0.54 nm.