The optimal control theory is used to solve various control tasks formulated for molecular systems with increasing complexity. Having the pulse at hand which solves the control task (the optimal pulse), in a second step, the extent is proven to which liquid-crystal spatial light modulators (LC-SLM) are capable to reproduce the optimal pulse and thus to solve the control task. Our calculations illustrate that additional insight into the control of molecular dynamics might be obtained if pulse shapers with a different number of cells are applied. (C) 2002 Elsevier Science B.V. All rights reserved.