Compound and labeled biological substance using the same

A compound represented by General Formula (1),

• in the General Formula (1), R1 to R4 represent an alkyl group which may have a substituent, an aryl group, a heteroaryl group, or —(CH2—CH2—O)m—R21, where m is 1 to 10 and R21 represents an alkyl group which may have a substituent,
• R11 to R13 represent a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an amino group, or a halogen atom, where at least one of R11 to R13 is an aryloxy group or an arylthio group, and adjacent groups may be bonded to each other to form a 5-membered or 6-membered ring,
• n is an integer of 1 to 3,
• L1 and L2 represent an alkyl group which may have a substituent or —(CH2—CH2—O)m—R21, where definitions of R21 and m are respectively the same as those of R21 and m in R1 to R4 of the General Formula (1),
• α1 and α2 are 0 or 1,
• a ring Z1 and a ring Z2 represent a 6-membered ring formed of a ring-constituting atom selected from a carbon atom and a nitrogen atom, may have a substituent, and may form a fused ring, provided that at least one of the ring Z1 or the ring Z2 is a benzene ring represented by General Formula (Zα) or a nitrogen-containing 6-membered ring satisfying the following definition (Zβ),
• in the General Formula (Zα), R22 represents an alkyl group, an alkoxy group, a sulfo group, a sulfonamide group, a nitro group, or a halogen atom,
• R23 to R25 represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a sulfo group, a sulfonamide group, a nitro group, or a halogen atom, where adjacent groups may be bonded to each other to form a fused ring,
• a structure represented by General Formula (Zα) is bonded, at a position of *, to a heterocyclic ring containing a nitrogen atom in General Formula (1) so that R22 is at an ortho position with respect to the nitrogen atom to which L1 or L2 is bonded,
• the definition (Zβ):
• a nitrogen-containing 6-membered ring in which a ring-constituting atom located at an ortho position with respect to a nitrogen atom to which L1 or L2 is bonded is a nitrogen atom, the ring-constituting nitrogen atom located at the ortho position may be substituted with a substituent,
• at least one of R1 to R4, L1, or L2 contains a structure represented by —(CH2—CH2—O)m—R21, where definitions of R21 and m are respectively the same as those of R21 and m in R1 to R4 of the General Formula (1),
• at least one of the substituents contained in L1 and L2 and possessed by the ring-constituting nitrogen atom located at the ortho position in the definition (Zβ) includes a substituent capable of being bonded to a carboxy group or a biological substance, and
• in a case where at least one of Z1 or Z2 is the nitrogen-containing 6-membered ring satisfying the definition (Zβ), two of the substituents contained in L1, L2, and R1 to R4 and possessed by the ring-constituting nitrogen atom located at the ortho position may be bonded to each other to form a ring containing a methine chain having a repetition number of 2n+3, provided that the compound represented by the General Formula (1) is a neutral compound.