The dynamics of a laser-driven nuclear wave packet on two coupled potential energy surfaces with 2 degrees of freedom, modeling the torsion of a C-C double bond interacting with a vibrational mode, is studied by numerically solving the time-dependent Schrodinger equation. An optimal control scheme is employed to determine the laser field to realize a nano-switch for cis-trans isomerization. The basic mechanism of the controlled isomerization process as well as the features of the optimal laser field and its dependence on the final time chosen for the optimization are studied in detail.