Heated vapor of tryptophan and its chemical analogs can be seeded into inert carrier gases undergoing supersonic expansions. The expansions remove most internal energy from the molecules (T_vib < 100 K, T_rot < 10 K), resulting in excitation spectra that show discernible vibrational and even rotational structure. Generally more than one 0-0 transition is present in the excitation spectra, arising from “frozen” populations of different conformations of the tryptophan analogs. This fact makes possible the measurement of fluorescence lifetimes as a function of the S₁ conformations chosen for excitation. We have carried out a number of lifetime measurements on conformers of different bare molecule tryptophan analogs as well as solvent complexes with indole chromophores by using the technique of time-correlated single photon counting. The complete set of lifetimes measured lends some insight into ¹L_a emission in gas phase indole chromophores as well as to the theory of multiexponential tryptophan fluorescence in solution.