An experiment related to the measurement of fluorescence lifetime for an undergraduate instrumental analysis or physical chemistry laboratory that highlights relative rates of electronic transitions in molecules and introduces students to data collection of a pulsed signal is illustrated. The experiment of the long fluorescence lifetime of Ru(bpy)[subscript 3][superscript 2+] around 600 ns was performed with aqueous solutions using light-emitting diode as an excitation source which allowed data to be collected on a modest oscilloscope.