 Consequently, most chemosensors are described as being either colorimetric (ground state) or luminescent (excited state, fluorescent or phosphorescent).Colorimetric chemosensors give rise to changes in their absorption properties (recorded using ultraviolet–visible spectroscopy), such as in absorption intensity and wavelength or in chirality (using circularly polarized light, and CD spectroscopy).In contrast, then in the case of luminescent chemosensors, the detection of an analyte, using fluorescence spectroscopy, gives rise to spectral changes in the fluorescence excitation or in the emission spectra, which are recorded using a fluorimeter.