TECHNOLOGY FOCUS - POLYMERS - Preparation (disclosed): Raw materials of formulae: V'2-T(-X)-V'3 and W'2-L-W'3 are reacted, resultant product of formula: W'2-(L-T(-X))g-V'3 is subjected to introduction terminal group using compounds of formulae: R-V'4 and R-W'4, to obtain polymer of formula: R-(L-T(-X)-)g-R. Preferred Structure: The polymer having repetiting unit (1) is of formula (9). At least one of repetition unit (1) of polymer is preferably of formula: -(Ar3-) (10).V'2-V'4,W'2-W'4=halo, alkyl sulfonate group, aryl sulfonate group, arylalkyl sulfonate group, alkyl stannyl group, aryl stannyl, arylalkyl stannyl, boric-acid-ester, sulfonium methyl group, phosphonium methyl group, phosphonate methyl group, mono-halogenated methyl group, boric-acid residue, formyl group, or vinyl;g=2 or more;R11-R14= monovalent heterocyclic group optionally having aryl group, alkyl, alkoxy, or substituent optionally having hydrogen or substitutent;R15=monovalent group optionally having hydrogen or substituent;s,t=2-12;andAr3=bivalent heterocyclic group optionally having bivalent aromatic hydrocarbyl optionally having substituent or substituent.R11-R14 are same, and s and t are same integer. The hydrogen of aryl group, alkyl, alkoxy, or substituent of heterocyclic group of R11-R14 is optionally substituted by fluorine. When two or more R11-R14 exists, R11-R14 are same or different. Preferred Definitions:    L=divalent organic group of formula (2);    X=monovalent organic group of formula (8);    Ar1=bivalent heterocyclic group optionally having optionally substituted bivalent aromatic hydrocarbyl or substituents;    R1-R4,R6-R9=R11;    m,n,o,p,q,r=0-10;    m+n+o,p+q+r=2-20;    T=trivalent organic group of formulae (3 - 7);    R5=H, alkyl, aryl, or cyano;and    R10=monovalent group optionally having hydrogen or substituent.    At least one of m and o is integer greater than or equal to 1. At least one of p and r is an integer greater than or equal to 1.    EXAMPLE - 5-Tributylstannane-2-(5-(5-(5-tributylstannane-3-hexyl thiophen-2-yl)thiophen-2-yl)thiophen-2-yl)-3-hexylthiophene (46 mg), 5-(3,5-dibromophenyl)-3-hexyl-2-(3-hexyl-5-phenylthiophen-2-yl)thiophene (27.5 mg), dry toluene (0.5 mL), and tetrakis triphenylphosphine palladium (0) (4.4 mg) were heat-stirred for three days. The reaction solution was filtered and concentrated under reduced pressure, resultant solid material was dissolved using chloroform, poured into methanol and precipitated, to obtain polymer (28 mg) of formula (11).