A toolkit of time-propagation operators, to be stored and recalled as needed, is incorporated into the algorithms for the optimal control of quantum systems. Typically, the control field epsilon(t) revisits the same values many times during the full time evolution. This repetition may be utilized to enhance efficiency through a convenient toolkit of propagators where the propagators are computed and stored only at a small number of discrete electric-field values in the dynamic range epsilon(min)less than or equal toepsilon(t)less than or equal toepsilon(max). At each time step of the controlled evolution a specific member of the pre-calculated toolkit is selected as dictated by the local control field value. The toolkit can reduce the cost of control field design by a factor scaling as similar toN for quantum systems described in a basis set of N states. Optimal control with the toolkit is demonstrated for systems up to dimension N=30. (C) 2003 American Institute of Physics.