TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Oligothiophene cross-linked by double aldehyde group is subjected to Knoevenagel condensation reaction in the presence of solvent and catalyst, and receptor-type oligothiophene is produced. Preferred Compound: The receptor type oligothiophene is preferably of formulae (II)-(VII).D,D1=cross-linked conjugated electron donor group chosen from 13 groups e.g. groups of formulae (i)-(v);A,A1=cross-linked conjugated receptor donor groups chosen from 10 groups e.g. groups of formulae (vi)-(x);andR3,R4=R1.Preferred Composition: The catalyst is alkali compound, preferably alkyl amine, more preferably triethylamine. The reaction is carried out in protective gas, preferably argon gas atmosphere. Alternately, the catalyst is acid catalyst, preferably weak acid catalyst chosen from ammonium acetate, ammonium propionate and ammonium butyrate. The solvent is acid solution, preferably chosen from acetic acid, propionic acid and butyric acid. The usage amount of catalyst is 10-30 mol%, preferably 20 mol%. Preferred Definitions:A2=organic small molecular dye groups chosen from 30 groups e.g. groups of formulae (xi) to (xv).    R5,R6=R1;    X=anion chosen from halogen ion, tetrafluoroborate ion, hexafluorophosphate ion, sulfate ion and trifluoromethyl sulfate ion;and    n=1-30, preferably 1-10.    SPECIFIC COMPOUNDS - 55 Receptor-type oligothiophenes e.g. ethyl (2E)-2-cyano-3-(5-(5-(5-((1Z)-3-ethoxy-2-isocyano-3-oxoprop-1-en-1-yl)-3-octylthiophen-2-yl)thiophen-2-yl)-4-octylthiophen-2-yl)prop-2-enoate of formula (Ia), ethyl (2E)-2-cyano-3-(5-(5-(5-(5-(5-((1Z)-3-ethoxy-2-isocyano-3-oxoprop-1-en-1-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)thiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)prop-2-enoate, ethyl (2Z)-3-(5-(5-(5-(5-(5-(5-(5-(1-cyano-2-ethoxy-2-oxoethylidene)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)thiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)-2-isocyanoprop-2-enoate, (2E)-3-(5-(5-(5-(7-(5-(5-(5-((1Z)-2-cyano-2-isocyanoeth-1-en-1-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)-2,1,3-benzothiadiazol-4-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)-2-isocyanoprop-2-enenitrile and 1,3-diethyl 2-((5-(5-(5-(5-(5-(5-(5-(3-ethoxy-2-(ethoxycarbonyl)-3-oxoprop-1-en-1-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)-3-octylthiophen-2-yl)thiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)-4-octylthiophen-2-yl)methylidene)propanedioate are specifically claimed.