Solvent:

The changes in the "polarity" or hydrogen bonding ability of the solvent might also significantly affect the fluorescent behaviour of the analyte. The difference within the effect of solvent on the fluorescence is attributed to the difference within their ability to stabilise the ground and excited states of the fluorescent molecule.  This alters the possibility and the energy of absorption and emission both bands.

Besides solvent polarity, solvent viscosity and solvents along with heavy atoms also affect fluorescence and phosphorescence.  An increased viscosity increases fluorescence as the deactivation because of collisions is lowered. A higher fluorescence is observed while the solvents do not holds heavy atoms although phosphorescence increases because of the presence of heavy atoms in the solvent.

Therefore, the fluorescence features of probe molecules might be used to make inferences about their immediate microenvironments.