Mixed supersonic expansions of dimethyl amino benzonitrile, DMABN, with the molecules cyclohexane, acetone, methanol, acetonitrile, dichloromethane, chloroform, and carbon tetrachloride resulted in fluorescence spectra which are best interpreted in terms of the processes in the expansion of monomer cooling, monomer complexation with substrate, dimer formation, and dimer complexation with substrate, for all complexing molecules except CHCl 3 and CH 2 Cl 2 . In the last two cases, clusters can be attributed to TICT state formation.