The possibility of using time-resolved vibronic spectroscopy for spectral analysis of mixtures of chemical compounds with similar optical properties, when traditional methods are inefficient, is demonstrated by using the method of computer simulation. The analysis is carried out by the example of molecules of a series of polyenes (butadiene, hexatraene, octatetraene, decapentaene, and decatetraene), their various cis- and trans-rotational isomers, and phenyl-substituted polyenes. Ranges of relative concentrations of molecules similar in their spectral properties, where reliable interpretation of time-resolved spectra of mixtures and both qualitative and quantitative analyses are possible, are determined. The use of computer simulation methods for oprimizing full-scale experiments in femtosecond spectroscopy is shown to hold much promise.