The theory of optimal control together with that of transient probe absorption spectroscopy are applied for control and detection of molecular wave packet dynamics in the weak response regime. We obtain a globally optimal pump-dump control field which drives the initial state to the predefined target, focused at the inner-turning point region of the electronic ground state potential. As for the detection, we calculate both the integrated and the dispersed transient pump-dump-probe absorption signals and adopt the difference detection schemes to reveal the optimally controlled molecular dynamics.