One of the major unsolved problems in the physical electrochemistry of liquid/liquid systems is the microscopic structure of the interfacial region. We propose that a picosecond time-dependent fluorescence following an excitation of amphiphilic solutes adsorbed at the interface could be used to probe the width of the interface. We examine the feasibility of this by a molecular dynamics computer simulation of solvation dynamics at the water/octanol interface. We show that the time-dependent solvent response is very sensitive to the location of the probe at the normal interface-the signature of a molecularly sharp interface. Simulation of the solvent response in a more diffuse interface shows a decreased dependence of the response on the location of the probe.