TECHNOLOGY FOCUS - POLYMERS - Preferred Component: (I) can be repeating units of formula (IV) or (V). (II) can be repeating units of formula (VI), (VII), (VIII), (VIIII), (X), (XI), or (XII).R5, R6, R7 = 1-20C alkyl, 6-60C aryl, 7-60C arylalkyl, monovalent heterocyclic compounds having 4-60C;n = 1-4;l = 1-5;m = 1-3;R8-R12 = 1-20C alkyl, 1-20C alkoxy, 1-20C alkylthio, 1-60C alkylsilyl, 1-40C alkylamino, 6-60C aryl, 6-60C aryloxy, 6-60C arylsiyl, 6-60C arylamino, 7-60C arylalkylsilyl, 7-60C arylalkylamino, 8-60C arylalkenyl, 8-60C arylalkynyl, 4-60C monovalent heterocyclic compounds, or cyano;i, j = 0-4;k = 0-5;h = 1-2;a, b = 0-3;R13, R16, R17, R20-R24, R29 = 1-20C alkyl, 1-20C alkoxy, 1-20C alkylthio, 1-60C alkylsilyl, 1-40C alkylamino, 6-60C aryl, 6-60C aryloxy, 6-60C arylsiyl, 6-60C arylamino, 7-60C arylalkyl, 7-60C arylalkoxy, 7-60C arylalkylsilyl, 7-60C arylalkylamino, 8-60C arylalkenyl, 8-60C arylalkynyl, 4-60C monovalent heterocyclic compound, or cyano;c, d = 0-4;R14, R1, R17, R20, R25-R28 = H, 1-20C alkyl, 6-60C aryl, 7-60C arylalkyl, 4-60C monovalent heterocyclic compound, or cyano;e - 0-5;f = 0-3;g = 0-2;X1 = O or S;o, p = 0-4;X2 = O, S, N-R24, or SiR25R26;X3, X4 = C or C-R27;R24-R27 = H, 1-20C alkyl, 6-60C aryl, 7-60C arylalkyl, or 4-6C monovalent heterocyclic compound;Ar5 = arylene or divalent heterocyclic compound;q, r = 0-4.Two or more of R8-R12 may be connected to form a ring. When R8, R9, and/or R10 is a group containing an alkyl chain, methyl, methylene, and/or methine constituting the alkyl chain may be substituted with a group containing a hetero atom. One or two of the substituents of (8) on a benzene ring are groups from alkoxy, aryl substituted with alkoxy, aryloxy, or arylalkoxy. Two or more R13-R16 may be connected to form a ring. When one or more R13- R16 are a group containing alkyl chain, methyl, methylene, and/or methine constituting the alkyl chain may be substituted with a group containing a hetero atom. R21s may be connected to form a ring. When R21 is a group containing alkyl chain, methyl, methylene, and/or methine constituting the alkyl chain may be substituted with a group containing a hetero atom. R22 and R23 may be connected to form a ring. When one or more R22 and R23 are a group containing alkyl chain, methyl, methylene, and/or methine constituting the alkyl chain may be substituted with a group containing a hetero atom. Two or more R24-R29 may be connected to form a ring. When one or more R24 and R29 are a group containing alkyl chain, methyl, methylene, and/or methine constituting the alkyl chain may be substituted with a group containing a hetero atom. EXAMPLE - Under argon atmosphere, 1,4-bis(propylene boronate)-2,5-di(3,7-dimethyloctyloxy) (321 mg), 4,7-dibromo-benzothiadiazol (161 mg), and aliquat 336 (221 mg) were dissolved in toluene (30 ml) and added with aqueous solution (30 ml) of potassium carbonate (238 mg). The mixture was added with tetrakis(triphenylphosphine)palladium (1.27 mg) and heated under reflux for 20 hour, then cooled. The solution was separated, and the organic layer was washed with water. The organic layer was dropped in methanol (300 ml) and the deposited precipitate was filtered off. The precipitate was purified to obtain a polymer. The polymer was dissolved in toluene. The solution and 25% ammonia water were mixed and stirred for 3 hours at room temperature. It was poured into methanol, stirred, filtered, and dried under reduced pressure for 2 hours at 50 degreesC to produce 231 mg polymeric fluorescent substance having a fluorescent peal wavelength of 570 nm and strong fluorescence.