In this work, a combination of a thin layer of Copper (II) phthalocyanine (CuPc) and TIPS-pentacene crystal was used to enhance the photo-sensing spectrum of photo- sensitive organic field-effect transistors (photo-OFETs). In TIPS-pentacene/CuPc bi-layer devices, the different conduction path not only reduced the total number of traps but also enhanced the sensing spectrum. It was found that, though the TIPS-pentacene was able to sense only blue and green colour well, and CuPc was able to sense only red and green colour well; the TIPS-pentacene/CuPc bi-layer were able to sense all three colors, enhancing the range of sensing. On illumination, bi-layer TIPS-pentacene/CuPc OFETs exhibited higher values of shift in threshold voltage (|ΔV TH |) compared to neat TIPS-pentacene and bare CuPc OFETs, due to change in the spatial distribution in the trap state density and associated pattern of trapping of photo-generated charge carriers. It was also found that the values of photo-responsivity (R max ) and photo-detection time for the bi-layer OFETs were in between that for OFETs with TIPS-pentacene or CuPc. © 2019