This paper highlights the recent progress for organic small molecule and polymer type thin film transistors (OTFTs). In order to better understand the conduction process and mapping of limiting factors, the structural variation between top and bottom contact organic TFT is examined. Also, the analytical models concerning to empirical parameters are discussed for forecasting the performance of organic transistor before a real realization. Various organic materials for dielectric, substrate, semiconductor and electrode with their performance are emphasized. Organic devices are specially designed for fabricating cost-effective printing methods. Therefore, various solution processed organic TFTs are reviewed, where most transistors are analyzed based on bottom contact positioning. In order to enhance the transistor parameters; various techniques are deeply analyzed and a quantitative progress in threshold voltage, mobility, sub-threshold slope, on-off ratio and current is projected. The role of self-assembled mono-layer is highlighted along with reliability of organic transistors. Some of leading applications convincing potential usage of OTFTs are emphasized with the passage of time as well.