Multilayered Langmuir-Blodgett (LB) films at different mole fractions of 9-phenyl fluorene (9PF) have been prepared using two different matrices viz. stearic acid (SA) and polymethyl methacrylate (PMMA). The spectroscopic properties of the mixed LB films, solution and microcrystal have been compared using absorption, steady-state fluorescence, and excitation spectroscopy. The spectroscopic studies give evidence of formation of excimeric sites in 9PF-SA LB films, while formation of dimeric species along with the excimeric sites have been evidenced in case of 9PF-PMMA LB films. (C) 2003 Elsevier Science B.V. All rights reserved.