In this Letter we present a framework for the use of continuously phase modulated radio-frequency pulses for heteronuclear decoupling in NMR of Liquid Crystals. Within this framework, we found new sets of heteronuclear decoupling sequences using numerical optimisation. These sequences and supercycles are tested experimentally on a model liquid crystal, and their performance is compared with standard heteronuclear decoupling sequences. (C) 2002 Elsevier Science B.V. All rights reserved.