Abstract: The following formula is an example of a phosphole compound of the present invention. The phosphole compound of the present invention has the characteristic of maintaining a high fluorescence quantum yield in a wide range of solvents from low-polarity solvents to high-polarity solvents, as well as the characteristic in which the fluorescence wavelength shifts to the longer wavelength side as the polarity of the solvent increases. Because of these characteristics, the phosphole compound of the present invention is expected to be used, for example, for quantitatively determining the polarity in the environment therearound by using the absorption wavelength and fluorescence wavelength thereof, or used as a new fluorescent probe dye or a highly efficient luminescent material in organic electronic devices.

Abstract: The following formula is an example of a phosphole compound of the present invention. The phosphole compound of the present invention has the characteristic of maintaining a high fluorescence quantum yield in a wide range of solvents from low-polarity solvents to high-polarity solvents, as well as the characteristic in which the fluorescence wavelength shifts to the longer wavelength side as the polarity of the solvent increases. Because of these characteristics, the phosphole compound of the present invention is expected to be used, for example, for quantitatively determining the polarity in the environment therearound by using the absorption wavelength and fluorescence wavelength thereof, or used as a new fluorescent probe dye or a highly efficient luminescent material in organic electronic devices.