A photonic crystal (PC) waveguide structure has been imprinted onto a nonlinear optical (NLO) polymer using thermal nanoimprint lithography (NIL). The imprint characteristics of Disperse Red 1 doped poly (methylmethaerylate) as the NLO polymer are evaluated by atomic force microscope. A waveauide structure with a uniform height of 650 nm is obtained at an imprint temperature of 120 degrees C. A peeling problem at the interfaces between constructing layers is solved by preparation of an appropriate substrate structure. Finally, polarized reflectivity measurement was performed for the imprinted PC waveguide structure. Several sharp dips corresponding to the formation of photonic band dispersion are observed. It was demonstrated that NIL is a direct path to the precise patterning of PC waveguide structures. (c) 2006 American Vacuum Society.