Abstract: A dithienophosphorine compound having a cation represented by the formula (wherein Y represents an oxygen atom or a sulfur atom; R1 represents a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heteroaryl group; R2 represents a hydroxy group, an alkyl group, an alkoxy group, an alkenyl group, an alkynyl group, an aryl group, or a heteroaryl group; R3, R4, R5, and R6 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, or an aryl group; R7 and R8 each independently represents an arylene group or a heteroarylene group; R9 and R10 each independently represent a hydrogen atom, a halogen atom, a sulfonyl group, an alkyl group or an aryl group; each group may have one or more substituents; and R3, R4, and R7 may bind to each other and/or R5, R6, and R8 may bind to each other to form a ring together with an adjacent nitrogen atom) is an organic compound that has a maximum absorption wavelength in the NIR-II region (from 1000 to 1500 nm) although th

Abstract: A phosphole compound represented by the formula (wherein Ar1 and Ar2 are the same or different, and represent an optionally substituted aromatic hydrocarbon ring or an optionally substituted heteroaromatic ring; Ar3 represents a divalent ?-conjugated unit; R1 represents an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; R2 and R3 are the same or different, and represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; and Z represents a reactive group) can provide a fluorescent dye capable of maintaining a high fluorescence quantum yield irrespective of solvent polarity, and providing an improved fluorescence quantum yield and light resistance even in environments containing large amounts of water.

Abstract: A phosphole compound represented by the formula (wherein Ar1 and Ar2 are the same or different, and represent an optionally substituted aromatic hydrocarbon ring or an optionally substituted heteroaromatic ring; Ar3 represents a divalent ?-conjugated unit; R1 represents an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; R2 and R3 are the same or different, and represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group, or an optionally substituted heteroaryl group; and Z represents a reactive group) can provide a fluorescent dye capable of maintaining a high fluorescence quantum yield irrespective of solvent polarity, and providing an improved fluorescence quantum yield and light resistance even in environments containing large amounts of water.