NOVELTY - Thiophene and thienylenevinylene units containing polymer (I), is new.    USE - (I) is useful in organic field effect transistor and organic solar cell (claimed).    ADVANTAGE - (I): can be directly coated on the substrates to form organic semiconductor films, and large-scale device may be manufactured without the need for an expensive vacuum system, thus reducing the production cost; exhibits excellent flatness and high crystallinity, thus providing improved charge mobility; and exhibits high oxidative stability due to its high ionization energy, thus providing the organic field effect transistors and organic solar cells having improved efficiencies.    DETAILED DESCRIPTION - Thiophene and thienylenevinylene units containing polymer of formula (I), is new.    R1-R6 = 1-25C alkyl, 1-25C alkoxy, 1-25C haloalkyl, 6-30C aryl or H;    A = benzo(1,2,5)thiadiazol-4,7-diyl, thieno(3,4-b)pyrazine-5,7-diyl, thiophene-2,5-diyl, thiazole-2,5-diyl, (1,3,4)thiadiazole-2,5-diyl, benzo(1,2,5)selenadiazole-4,7-diyl, 2-selena-4,7-diaza-indene-1,3-diyl, 2,3-dihydro-thieno(3,4-b)(1,4)dioxine-5,7-diyl, selenophene-2,5-diyl, selenazole-2,5-diyl, 2,3-diphenyl-quinoxaline-5,8-diyl, 5-(7-(3,5-thiophenylene)benzo(c)(1,2,5)thiadiazol-4-yl)thiophen-2-yl, benzo(1,2,5)oxadiazole-4,7-diyl, 5~14,11-dithia-4,6,10,12-tetraazatricyclo(7.3.0.03,7)dodeca-1(12),2,4,5,7,9-hexaen-2,8-diyl, substituted 5 lambda 4,11-dithia-4,6,10,12-tetraazatricyclo(7.3.0.03,7)dodeca-1(12),2,4,5,7,9-hexaen-2,8-diyl compounds of formula (II), substituted 5 lambda 4,11-dithia-4,6,10,12-tetraazatricyclo(7.3.0.03,7)dodeca-1(12),2,4,5,7,9-hexaen-2,8-diyl compounds of formula (III), substituted 2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione compounds of formula (IV), substituted 2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione compounds of formula (V), substituted 3,6-diphenyl-2,5-dihydro-pyrrolo(3,4-c)pyrrole-1,4-dione compounds of formula (VI), substituted thieno(3,4-c)pyrrole-4,6-dione compounds of formula (VII), substituted thieno(3,4-c)pyrrole-4,6-dione compounds of formula (VIII), substituted thieno(3,4-c)pyrrole-4,6-dione compounds of formula (IX) or substituted thieno(3,4-c)pyrrole-4,6-dione compounds of formula (X);    X1, X2 = S, O, or Se;    R7-R10 = 1-30C alkyl, 1-30C alkoxy or 1-30C haloalkyl;    R11, R12 = 1-30C alkyl;    n, l = 1-1000; and    m = 0-1000.    INDEPENDENT CLAIMS are also included for:    (1) an organic field effect transistor, comprising: an organic semiconductor layer arranged on a substrate and containing (I); a gate electrode arranged above or below the organic semiconductor layer to overlap the organic semiconductor layer; and a source electrode and a drain electrode connected to both ends of the organic semiconductor layer, respectively; and    (2) an organic solar cell, comprising: a first electrode (21) arranged on a substrate; an organic active layer (25) arranged on the first electrode and containing (I); and a second electrode (29) arranged on the organic active layer.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of an organic solar cell.    First electrode (21)    First charge transport layer (23)    Active layer (25)    Second charge transport layer (27)    Second electrode (29)