The excited state dynamics of 3-methylindole are investigated with the goal of further characterizing the nonadiabatic interaction giving rise to ' La-%, mixing in its excited singlet state. Both the bare molecule and its clusters with polar species display evidence of coupling between these two close-lying states. By using a series of successively more polar ligands, it is shown that the strength of the interaction between the ' Lb and 'La states can be "tuned", permitting the observation of progressive changes in excited state behavior. This enables us to relate the present results to previous studies conducted in this and a number of other laboratories. While each of these has concentrated on the measurement of a particular excited state phenomenon as a signature of 'La state coupling, the results presented here are used to show how they can be successfully integrated into a more general picture of 'La-lLb state coupling in indoles.