There are provided fluorescent compounds that can be used for DNA
sequencing, measurement of physiologically active substance or the like
based on fluorescence immunoassay and so forth.
Compounds represented by the formula (I) (V.sup.1 to V.sup.6 represent a
hydrogen atom or a functional group selected from the group consisting of
a halogen atom, an alkyl group, an alkenyl group, a group that can form a
covalent bond with a compound to be labeled and the like, and V.sup.1,
V.sup.2 and others may bind to each other to form a saturated or
unsaturated ring; R.sup.1 represents a hydrogen atom or a functional group
selected from the group consisting of an alkyl group, an aryl group and a
heterocyclic group; R.sup.3 and R.sup.4 represent an alkyl group, and
R.sup.3 and R.sup.4 may bind to each other to form a ring; Q represents a
group of atoms required to form a methine dye chromophore; and m and n
represent 0 or 1, provided that m+n is 1) or salts thereof
##STR1##
