The theory of optimal control of molecular dynamics via a two-photon process is developed in terms of the density matrix in Liouville space. Applications are made to the generalized Tannor-Rice pump-dump molecular control scheme involving two and three electronic states. The solutions of two coupled eigenequations directly give the optimal pump and dump control fields with respect to the target. The globally optimal solutions are analyzed and the numerical implementation is discussed. Formal comparisons with pump-probe (chi((3))) optical processes are also given.