The characteristics and benefits of two types of cross-linking prepolymers with low glass transition temperature (Tg) for nanoimprinting are reported. They are soluble in organic solvents and their solutions can be processed like those of common thermoplastics. The imprinted patterns receive high thermal and mechanical stability through cross-linking polymerization. The course of the polymerization was investigated to determine the appropriate conditions for the imprint process. In thermally cross-linked polymers mr-I 9000, the cross-linking occurs during imprinting. Process time and temperature depend on the polymerization rate. Volume shrinkage during the polymerization does not adversely affect imprinting. Photochemically cross-linked polymers mr-L 6000 make possible imprint temperatures below 100 °C and short imprint times. The Tg of the prepolymer determines the imprint temperature. The cross-linking reaction and structural stabilization is performed after imprinting. 50-nm trenches and sub-50-nm dots confirm the successful application of the polymers.