We report on low operating voltage transistors based on polymer-sorted semiconducting (6,5) single-walled carbon nanotube (SWNT) networks processed from solution at room temperature. The (6,5) SWNTs were separated from the as-received carbon nanotubes mixture using a polyfluorene-based derivative as the sorting and dispersing polymer agent. As-prepared devices exhibit primarily p-type behavior with channel current on/off ratio >103 and hole mobility ≈2 cm2 V−1 s−1. These transistor characteristics enable realization of low-voltage unipolar inverters with wide noise margins and high signal gain (>5). Polymer/(6,5) SWNT transistors were also fabricated on free-standing polyimide foils. The devices exhibit even higher hole mobility (≈8 cm2 V−1 s−1) and on/off ratios (>104) while remaining fully functional when bent to a radius of 4 mm.