We report on the fabrication of efficient organic distributed feedback (DFB) lasers with thermally-nanoimprinted active films, emitting between 565 and 580 nm. The use of thermal-NIL has allowed, as opposed to room temperature or solvent-assisted techniques, high grating quality and excellent modulation depth. The 155°C heat exposure of the NIL process, does not significantly affect the thermal and optical properties of the active material (polystyrene films doped with a perylenediimide derivative). These devices combine a simple and low-cost preparation method with good laser characteristics, i.e. thresholds of 1 μJ/pulse, single-mode emission with linewidths below 0.2 nm and photostability half-lives of ~ 10⁵ pump pulses under ambient conditions. In comparison to more standard DFBs with gratings on the substrate, their fabrication is much easier, while they show a similar laser performance.