NOVELTY - A polymer compound has number average molecular weight of 103-108, and comprises specific repeating units.    USE - For forming polymeric thin film used in organic thin film transistor, organic solar cell, optical sensor, electrophotographic photoreceptor, and spatial light modulation element (all claimed).    ADVANTAGE - The polymer compound efficiently forms a polymeric thin film.    DETAILED DESCRIPTION - A polymer compound has number average molecular weight of 103-108, and comprises specific repeating units of formula (1) and formula (2).    Ar1,Ar2=trivalent aromatic hydrocarbon group or trivalent heterocyclic group;    X1,X2=O, S, C(=O), S(=O), SO2, C(R1)(R2), Si(R3(R4), N(R5), B(R6), P(R7) or P(=O)(R8);    R1-R8=H, halogen, alkyl, alkyloxy, alkylthio, aryl, aryloxy, arylthio, arylalkyl, arylalkyloxy, arylalkylthio, acyl, acyloxy, amide, acid imide, imine residue, substituted (amino, silyl, silyloxy, silyl thio, silylamino), univalent heterocyclic group, heteroaryl oxy, heteroarylthio, arylalkenyl, aryl ethynyl, carboxyl, alkyl oxycarbonyl, aryloxy carbonyl, arylalkyl oxycarbonyl, heteroaryl oxycarbonyl, or a cyano group;    m=0 or 1;    n=1-6;    o=1-10;    p=0-2;    Y=O,S,C(R10)(R11), Si(R12)(R13) or n(R14);    R10-R14=R1;and    R9=R1 except hydrogen.    X1 and X2 are not same, R1 and R3, R3 and R4 mutually couples to form a ring. When m = 0, X1 is not equal to C(R1)(R2), X1 and Ar2 bonds to the adjacent position of aromatic ring of Ar1. When m is 1, X2 and Ar1 bonds to the adjacent position of aromatic ring of Ar2 and when m is 0, X1 and Ar1 bonds to the adjacent position of aromatic ring of Ar2.    INDEPENDENT CLAIMS are also included for the following:    (1) polymeric thin film containing the polymer compound, having film thickness of 1 nm to 100 microns;    (2) manufacture of polymeric thin film by spin coating, inkjet printing, dispenser printing or flexographic printing;    (3) organic thin film transistor containing the polymeric thin film;    (4) organic solar cell;    (5) optical sensor;    (6) electrophotographic photoreceptor; and    (7) spatial light modulation element.    DESCRIPTION OF DRAWING(S) - The figure shows outline sectional view of reverse stagger type organic thin film transistor.    base material (1)    polymeric thin film (2)    insulation film (3)    gate electrode (4)    source electrode (5)    drain electrode (6)