Oligoarenes as an alternative group of promising semiconductors in organic optoelectronics have attracted much attention. However, high-performance and low-cost opto-electrical devices based on linear asymmetric oligoarenes with nano/microstructures are still rarely studied because of difficulties both in synthesis and high-quality nano/microstructure growth. Here, a novel, linear asymmetric oligoarene 6-methyl-anthra[2,3-b]benzo[d]thiophene (Me-ABT) is synthesized and its high-quality microribbons are grown by a solution process. The solution of Me-ABT exhibits a moderate fluorescence quantum yield of 0.34, while the microribbons show a glaucous light emission. Phototransistors based on an individual Me-ABT microribbon prepared by a solution-phase self-assembly process showed a high mobility of 1.66 cm(2)V(-1) a large photoresponsivity of 12 000 A W-1, and a photocurrent/dark-current ratio of 6000 even under low light power conditions (30 mu W/cm(2)) The measured photoresponsivity of the devices is much higher than that of inorganic single-crystal silicon thin film transistors. These studies shod boost the development of the organic semiconductors with high-quality microstructures for potential application in organic optoelectronics.