The critical role of the mixing ratio of the semiconductor and polymer solutions on the performance and electro-mechanical stability of the flexible blend OFETs is investigated. An improvement in the OFET performance was observed with increasing fraction of polymer in the solution. The maximum field-effect mobility improved from 0.08 for neat TIPS-pentacene OFETs to 0.24, 0.25 and 0.57 cm2 V−1 s−1 for semiconductor:polymer blend OFETs with mixing ratio of 3:1, 1:1 and 1:3 respectively. Under stress conditions of VDS = VGS = −5 V for 1 h, the 1:3 blend devices outperformed other categories of devices with very small drain current decay of ∼2% and 11% and small threshold voltage shift of 0.05 V and 0.27 V before and after 1.27% (Rbend = 5 mm) tensile strain application respectively. These devices also exhibited superior reliability with least performance spread over 100 continuous transfer characteristics measurement cycles before and after application of strain. © 2018 Elsevier B.V.