Described herein are wavelength conversion films which utilize photostable organic chromophores. In some embodiments, wavelength conversion films and chromophores exhibit improved photostability. In some embodiments, a wavelength conversion film comprising luminescent compounds is useful for improving the solar harvesting efficiency of solar cells, solar panels, or photovoltaic devices. In some embodiments, a wavelength conversion film comprising multiple luminescent compounds is useful for greenhouse roofs. Some embodiments provide an improved solar light wavelength profile for improved plant nutrition and/or growth.