Rotationally resolved fluorescence excitation spectra of several vibronic bands in the S-1 <-- S-0 electronic transitions of styrene (STY) and phenylacetylene (PA) have been obtained. Confirming earlier low resolution results, we find that the origin band of PA is a b-type band but that the corresponding band of STY is an a-type band, showing that the S-1 state of PA is L-1(b) in character (like that of most other monosubstituted benzenes! but that the corresponding state of STY is L-1(a). The observed changes in the rotational constants of PA and STY that occur when the photon is absorbed are consistent with these assignments. Reversal in the electronic character of the S-1 state in STY is attributed to the presence of the "off-axis'' conjugating - CH=CH2 group, a suggestion that is supported by the observed polarizations of higher vibronic bands in both molecules.