Provided are any one of the following compounds and a fluorescently labeled biological substance having this compound.

##STR00001##

R.sup.1 to R.sup.27, L.sup.11, L.sup.12, and X.sup.+ represent a specific group, and at least one of R.sup.1 to R.sup.4 represents a substituted alkyl group.

In a case where at least one of R.sup.1 to R.sup.4 is an alkyl group having a carboxy group or a substituent capable of being bonded to a biological substance, at least one of R.sup.11 to R.sup.27 is an alkyl group or an aryl group, or at least one of R.sup.1 to R.sup.4, which does not correspond to the alkyl group having a carboxy group or an alkyl group having a substituent capable of being bonded to a biological substance, is an alkyl group having a sulfoalkyl group through a single bond or a linking group.

The total of n1 to n4 is an integer of 3 or more, and m=n1+n2+n3+n4−1 is satisfied.

At least one of R.sup.1 to R.sup.4, R.sup.13, L.sup.11 or L.sup.12 in Formula (1) and at least one of R.sup.1 to R.sup.4, R.sup.24, L.sup.11, or L.sup.12 in Formula (2) have a specific substituent.

The present invention relates to: a novel merocyanine-based compound which exhibits a fluorescence signal at a visible light region of at least 380 nm, and which may be used for detecting biomolecules; and a biomolecular labeling dye, kit and contrast agent composition comprising the same.

The present invention relates to novel methine dyes, methods for the preparation thereof and use thereof for dyeing plastics, especially polyamides, so as to obtain yellow to orange colourings with improved light fastness and improved thermal stability.

A heat sensitive transfer sheet that achieves high optical density and high light resistance without generating scumming. The heat sensitive sheet has a base material and a coloring material layer formed on the base material, and the coloring material layer includes a compound represented by the following formula (1) and a particular dye compound:

##STR00001##

wherein
R.sup.11 and R.sup.13 each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an unsubstituted aryl group or an aryl group having a substituent; and
R.sup.12 and R.sup.14 to R.sup.18 each independently represent a hydrogen atom or an alkyl group.

The present invention relates to: a novel merocyanine-based compound which exhibits a fluorescence signal at a visible light region of at least 380 nm, and which may be used for detecting biomolecules; and a biomolecular labeling dye, kit and contrast agent composition comprising the same.

The present disclosure embodies compounds, methods, and kits that are useful in connection with the detection of analytes of all types (e.g., biological molecules such as proteins, organic molecules, natural or synthetic molecules). The disclosure is particularly applicable to detection of proteins and nucleic acids using all types of membrane-based assays by techniques such as Western blotting, Dot blotting, Southern blotting, and Northern blotting.

Provided are a fluorescent dye and a preparation process and use thereof. The fluorescent dye is able to emit a long wavelength, is sensitive and specific to viscosity, and is used for a wide range of purposes, such as viscosity testing, fluorescent labeling, quantification or detection of proteins, enzymes or nucleic acids. In addition, it can be used as a fluorescent-activated probe.

Provided is an ink jet recording ink including: a colorant represented by the following Formula 1, in which an absorption maximum of a dry material of the ink jet recording ink is 700 nm to 1000 nm.

##STR00001##

The present invention relates to novel methine dyes, methods for the preparation thereof and use thereof for dyeing plastics, especially polyamides, so as to obtain yellow colorings with improved light fastness and improved thermostability.

The present invention relates to novel methine dyes, methods for the preparation thereof and use thereof for dyeing plastics, especially polyamides, so as to obtain yellow to orange colourings with improved light fastness and improved thermal stability.