[en] Laser-induced fluorescence excitation spectra of the bichromophoric molecule, 1,4-Di(1-naphthyl)propane (N4N(1,1')), and of 1-buthylnaphthalene (1-BuN) in a supersonic jet are reported. Comparison between the two spectra suggests that the two naphthalene moieties in the bichromophoric molecule do not interact strongly. Exciton splitting or evidence for excimer formation was not observed. However, the aliphatic substitution alone, cannot account for the significant red shift of the origin in the spectrum of the bichromophoric molecule