The rotationally resolved fluorescence excitation spectrum of the 0(0)0 band in the S1 <-- S0 transition, at almost-equal-to 318 nm, of the 1-cyanonaphthalene/triethylamine van der Waals complex has been recorded using laser-induced fluorescence in a molecular beam apparatus. This spectrum could be fitted to a pure a-type band. From the rotational constants a T-shaped geometry could be deduced.