High on-off ratio, low turn-on voltage and fast response time are most critical issues in the research and development of organic transistor. In the present work, we have fabricated vertical type organic transistor using 2,8-difluoro-indeno[1,2-b]fluorine-6,12-dione (IF-dione-F) as an organic active semiconductor and DMDCNQI as a n type buffer material. IF-dione-F shows n-type semiconductor property and relatively high electron mobility. The organic light emitting transistor (OLET) configuration is ITO (drain)/PEDOT:PSS/MEH-PPV/IF-dione-F/Metal (gate)/IF-dione-F/DMDCNQI/Metal (source). The characteristics of OLET were investigated from the measurements of current-radiance voltage characteristics, electron mobility and external quantum efficiency