Abstract: A compound represented by the formula (I) [R1 represents hydrogen atom or a substituent; R2, R3, R6, and R7 represent hydrogen atom, an alkyl group, a halogen atom, or a hydrophilic substituent; R4 and R5 represent an alkyl group or an aryl group; R8 and R9 represent a group cleaved by contact with an object substance for measurement; and X represents silicon atom, germanium atom, or tin atom] or a salt thereof, which is useful as a fluorescent probe that emits red fluorescence by contact with an object substance for measurement.

Abstract: A compound represented by the formula (I) (R1 represents a substituent on the benzene ring; R2 represents a monovalent substituent; R3 and R4 represent hydrogen atom, or an alkyl group; R5 and R6 represent an alkyl group, or an aryl group; R7 and R8 represent hydrogen atom, or an alkyl group; R9 and R10 represent hydrogen atom, or a monovalent substituent; and X represents silicon atom, germanium atom, or tin atom), or a salt thereof.

Abstract: A compound represented by the formula (I) (one of substituents represented by R1 is a trapping group for an object substance for measurement; R2 and R3 represent hydrogen, alkyl, or halogen; R4 and R5 represent alkyl or aryl; R6 and R7 represent hydrogen, alkyl, or halogen; R8 represents hydrogen, alkylcarbonyl, or alkylcarbonyloxymethyl, and X represents silicon, germanium, or tin, which can be used as a fluorescent probe that enables red color bioimaging using intramolecular photoinduced electron transfer.

Abstract: A compound represented by the formula (I) (R1 represents hydrogen atom or a monovalent substituent; R2 and R3 represent hydrogen atom, an alkyl group, or a halogen atom; R4 and R5 represent an alkyl group or an aryl group; R6 and R7 represent hydrogen atom, an alkyl group, or a halogen atom; R8 represent hydroxy group or a dialkoxyboranetriyl group; and X represents silicon atom, germanium atom, or tin atom), which is a novel fluorophore usable as a mother nucleus of an off/on type fluorescent probe not utilizing the intramolecular photoinduced electron transfer.

Abstract: A fluorescent gadolinium complex compound comprising a residue of gadolinium.1,4,7,10-tetraazacyclododecane-N,N?,N?,N??-tetraacetic acid or a residue of gadolinium.diethylenetriaminepentaacetic acid bound covalently with a group represented by the following general formula (I) (R1 represents hydrogen atom or a substituent R2, R4, R5 and R7 represent hydrogen atom, a halogen atom or a C1-6 alkyl group, and R3 and R6 represent hydrogen atom, a halogen atom or a C1-6 alkyl group), which is easily taken up into cells and useful as a probe observable by the fluorescence method and MRI.