NOVELTY - A thiophene pyrrole diketone and tetra carboxylic acid diimide copolymer (I).    USE - Copolymer for use in an active layer of an organic solar battery device, a light emitting layer of an organic electroluminescent device, and an organic semiconductor layer of an organic FET (all claimed).    ADVANTAGE - The copolymer has better dissolving property, high carrier mobility, strong absorbency, wide light absorption range, high solar utilization rate, and is prepared in a simple and controllable manner.    DETAILED DESCRIPTION - A thiophene pyrrole diketone and tetra carboxylic acid diimide copolymer has structure of formula (I). INDEPENDENT CLAIMS are also included for the following:    (1) a method for preparing a thiophene pyrrole diketone and tetra carboxylic acid diimide copolymer, which involves respectively providing a compound of formula (I1) and (I2), carrying out Stille coupling reaction for the compound of formula (I1) and (I2) in oxygen free environment containing a first catalyst and a first organic solvent to obtain thiophene pyrrole diketone and tetra carboxylic acid diimide copolymer    (2) an organic solar battery device, which comprises a substrate, where one surface is deposited with a base material taken as a conductive layer, and an anode is arranged on the conductive layer and coated with modified poly (3,4-ethylenedioxy thiophene) and poly (styrene sulfonic acid) active layer, which is coated on a surface of an insulating layer and a surface of a metallic aluminum layer as a cathode, where material of the active layer is a copolymer containing the thiophene and pyrrole diketone unit and tetracarboxylic acid diimide, and the copolymer has a structure of formula (I)    (3) an organic electroluminescent device, which comprises a substrate, where the surface is deposited with a conductive layer of an anode, and a light emitting layer that is coated on the conductive layer formed using lithium fluoride buffer layer. A metal aluminum layer is set as the cathode and arranged on the buffer layer. The light emitting layer comprises thiophene and pyrrole diketone unit and tetracarboxylic acid diimide copolymer    (4) an organic FET, which comprises a doped silicon chip, a silicon dioxide insulating layer for modifying an alkyl chlorosilane layer that is coated on an acid alkyl chlorosilane organic semiconductor layer, a source electrode and a drain electrode that are placed on an organic semiconductor layer. The organic semiconductor layer includes thiophene and pyrrole diketone unit perylene tetra carboxylic acid diimide copolymer.    n=1-100;    R1-R3=-H, 1-20C alkyl or 1-20C phenyl;    R4-R5=1-20C alkyl;and    R6=1-20C alkyl or alkoxy.    .    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of an organic solar battery device.'(Drawing includes non-English language text)'