Solvatochromism, dichroism and excited state dipole moment of azure A and methylene blue

► Photophysical properties of two thiazine dyes were recorded in various solvents. ► Ground and the excited states dipole moments of the dyes were estimated. ► The nature and extent of solvent-solute interactions were characterized. ► The spectral behavior of the dyes was investigated in a polar anisotropic medium.