The intermediate charge-transfer transients of 4-amino-N-methylphthalimide (4AMP) has been characterized by laser flash photolysis, steady-state and time-resolved fluorescence studies. 4AMP is a solvatochromic fluorescent dye. Transient solvation of 4AMP in binary supercritical fluids composed of 2-propanol and CO2 has been studied by frequency-domain fluorescence spectroscopy.