TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): Compound (I) or (II) is prepared by reacting a hydroxyl-substituted homocyclic or heterocyclic aromatic compound of formula (III) with an ethylenically unsaturated carbonyl chloride of formula Cl-C(=O)-C(R4)=C(R1)(R2) (IV) or its corresponding carboxylic anhydride, or an acetylenically unsaturated carbonyl chloride of formula Cl-C(=O)-CC-R3 (V). Preferred Component: The ethylenically unsaturated carbonyl chloride (IV) is crotonyl chloride, acryloyl chloride, methacryloyl chloride, pent-2-enoyl chloride, hex-2-enoyl chloride, hept-2-enoyl chloride, cinnamoyl chloride, 2-chlorocinnamoyl chloride, 4-fluorocinnamoyl chloride, or 4-methoxycinnamoyl chloride. The acetylenically unsaturated carbonyl chloride (V) is propiolic acid chloride, phenylpropiolic acid chloride, 2-butynoic acid chloride, 2-pentynoic acid chloride or 2-hexynoic acid chloride. The hydroxyl-substituted homocyclic or heterocyclic aromatic compound (Ill) is 2,5-dibromo-3-hydroxyethyl thiophene, 2,5-dibromo-3-hydroxymethyl thiophene, 2,5-dibromophenol, 2-bromophenol, 3-bromophenol, 4-bromophenol, 2,5-dibromo-1-(2-hydroxyethyl)benzene, 2-bromobenzyl alcohol, 3-bromobenzyl alcohol, 4-bromobenzyl alcohol, 4-hydroxyphenylboronic acid, 4-(hydroxymethyl)phenylboronic acid, 3-(hydroxymethyl)phenylboronic acid, 2,6-dibromo-4-(2-hydroxyethyl)-pyridine, 2,6-dibromo-3-(2-hydroxyethyl)pyridine, (S)-2,6-dibromo-4-(1-hydroxyethyl)pyridine, (R)-2,6-dibromo-4-(1-hydroxyethyl)pyridine, 2,6-dibromo-4-(hydroxymethyl)-pyridine, 2,6-dibromo-3-(hydroxymethyl)-pyridine, 2,6-dibromo-3-(3-hydroxypropyl)-pyridine, 3,6-dibromo-9H-2-hydroxycarbazole, 3,6-dibromo-9H-4-hydroxycarbazole, 2,7-dibromo-9-hydroxyfluorene, 2,7-dibromo-9-hydroxymethylfluorene, 1,4-dibromo-2-naphthol, 1,4-dibromo-2-naphthalenemethanol or 4,7-dibromo-2-hydroxybenzothiazole.    TECHNOLOGY FOCUS - POLYMERS - Preferred Component: The polymer further comprises repeating unit(s) derived from a comonomer (0.5-99.5 mole%) copolymerizable with (I) or (II), and comprising a divalent homocyclic or heterocyclic aromatic group Ar'optionally substituted with 1-20C-alkyl, 1-20C-alkoxy, 1-20C-alkylsulfate, phenyl and/or benzyl. The comonomer comprises the same homocyclic or heterocyclic aromatic group Ar'. The Ar'is 2,5 thienylene. SPECIFIC COMPOUNDS - 2 Compounds (I) are specifically claimed, e.g. 2,5-dibromo-3-hexylthiophene (Ia) or 2,5-dibromo-3-acetylethanolthiophene.    EXAMPLE - A bromothiophene (100 ml) was added with nickel(1,3-bis(diphenylphospino)propane)dichloride (5.19 g) and dry diethylether (300 ml), stirred in the presence of nitrogen, added dropwise with hexylmagnesium bromide (611 ml) at 0 degrees C, stirred overnight at room temperature, added 1M with hydrochloric acid for neutralization, extracted with diethyl ether, washed with saturated sodium bicarbonate solution, dried over magnesium sulfate, and purified to obtain 3-hexylthiophene. The obtained 3-hexylthiophene (10 g) was added with dimethyl formamide (100 ml), stirred in the dark at 0 degrees C, allowed to warm at room temperature, stirred for 48 hours, added with ice cooled sodium hydroxide (100 ml), and extracted with diethyl ether (100 ml). The obtained organic phase was washed with 2.5 M sodium hydroxide solution (100 ml), dried with magnesium sulfate, and purified to obtain 2,5-dibromo-3-hexylthiophene (Ia).