This paper presents the results of an experimental study of the dynamic characteristics of the laser fragmentation/laser-induced fluorescence (LF/LIF) process in nitrobenzene and para-nitrotoluene vapors under synchronized two-pulse laser irradiation. It is shown that if the values of the time delay between the pulses of fragmentation (248.4 nm) and excitation (247.87 nm) of NO fragments are in the range of 20-40 ns, the efficiency of the LF/LIF method can be increased several times.