We present gain and lasing results from a polyrotaxane consisting of a conjugated polymer (polyfluorene-alt-biphenylene) threaded through sugar macrocycles (Β -cyclodextrin). Encapsulation suppresses interchain charge separation, leading to lasing emission not observed in the unthreaded polymer, and enlargement of the stimulated emission in threaded polymer is observed. We demonstrate all-optical switching distributed feedback laser. © 2009 American Institute of Physics.