NOVELTY - Organic semiconductor material comprises carbazole and thiophene pyrrole diketone.    USE - The organic semiconductor material containing carbazole and thiophene pyrrole diketone is useful for organic solar cell, organic field effect transistor, organic electroluminescent device, organic optical storage, organic nonlinear material or organic laser device (all claimed).    ADVANTAGE - The organic semiconductor material can form a strong donor-acceptor structure, improves the stability of electronic devices, and it is good for reducing the material band gap so as to expand the sunlight absorption range, which improves the photoelectric conversion efficiency.    DETAILED DESCRIPTION - Organic semiconductor material comprises carbazole and thiophene pyrrole diketone, having the structure of Formula (I).    R1 and R2=1-20C alkyl; and    n=integer more than 1 and less than 100.    An INDEPENDENT CLAIM is a method for preparing the organic semiconductor material containing carbazole and a thiophene pyrroledione unit, comprising: (S1) at a temperature ranging from -100 degrees C to -25 degrees C, adding 2,7-dibromo-9-alkyl-9H-carbazole (A1) and n-BuLi into a first solvent according to the molar ratio in the range of 1:2 to 1:4, then adding 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (C1), and continuously reacting for 24-48 hours to obtain 9-alkyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (B1); (S2) at a temperature ranging from 10-30 degrees C, adding 5-alkylthienyl(3,4-c)-pyrrole-4,6-dione (A2) and a brominating agent into a second solvent according to the molar ratio in the range of 1:2 to 1:4, and reacting for 12-48 hours to obtain 1,3-dibromo-5-alkylthienyl(3, 4-c)-pyrrole-4,6-dione (B2); (S3) in a third solvent with a catalyst and an alkali solution, adding the 9-alkyl-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole (B1) obtained in the step (S1) and the 1,3-dibromo-5-alkylthienyl(3,4-c)-pyrrole-4,6-dione (B2) obtained in the step (S2) according to the molar ratio 1:a, carrying out a Suzuki reaction for 24-72 hours at 65-120 degrees C in order to obtain the organic semiconductor material containing carbazole and a thiophene pyrroledione unit (I), where a is greater than or equal to 0.95 and less than or equal to 1.05.