Fluorescent chromophores nicknamed BOPHY are provided. The chromophores may be readily synthesized in two steps from readily available reagents via the coupling of a pyrrole aldehyde or ketone with hydrazine, followed by reaction with BF.sub.3. The resultant symmetric and dimeric tetracycle is comprised of two BF.sub.2 units in six-member chelate rings, appended by pyrrole units on the periphery. The quantum yield of fluorescence for the unmodified compound and the tetramethyl variant are near unity, with values 95 and 92% respectively in CH.sub.2Cl.sub.2.

A compound excellent in chroma, light resistance and solubility. The compound has a structure represented by Formula (1).

##STR00001## wherein R.sub.1 and R.sub.2 each independently represent a linear or branched alkyl group having 1 to 12 carbon atoms, R.sub.3 represents a linear or branched alkyl group having 1 to 4 carbon atoms, an aryl group having a substituent, or an unsubstituted aryl group, and R.sub.4 represents an alkyl group having 1 to 4 carbon atoms; and R.sub.5 and R.sub.6 each independently represent a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, an alkyl group having a hydroxyl group at the terminal, an aryl group having a substituent, or an unsubstituted aryl group; and R.sub.5 and R.sub.6 may be combined to form a heterocycle.

The present invention relates to novel cationic azomethine direct dyes of formula (I) and the leuco forms thereof of formula (II), and also to the use thereof for dyeing keratin fibres, in particular human keratin fibres such as the hair: (I) (II) in which formula (I) or (II) X.sub.1, X.sub.2, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, n and n are as defined in the description. The compounds of formula (I) according to the invention can give powerful, chromatic and sparingly selective colourings with good colour build-up, which are resistant to the various attacking factors to which keratin fibres may be subjected, such as inclement weather, light, washing and perspiration.

##STR00001##

The present invention concerns an auxochrome substituent for an oxidative dye coupler. The auxochrome substituent enables ready developer reaction with the coupler to form azomethine and leuco dyes. Manipulation of the auxochrome substituent enables a bathochromic or hypsochromic shift of the light absorbance by the azomethine dye formed with the auxochrome substituted coupler.

The present invention concerns an auxochrome substituent for an oxidative dye coupler. The auxochrome substituent enables ready developer reaction with the coupler to form azomethine and leuco dyes. Manipulation of the auxochrome substituent enables a bathochromic or hypsochromic shift of the light absorbance by the azomethine dye formed with the auxochrome substituted coupler.

The present invention relates to fluorescent dyes of formula (I), including salts thereof, and extracellular vesicles and cells labelled with the fluorescent dyes. The present invention also relates to methods, uses and kits thereof.

##STR00001##

The subject of the present invention is a process for treating keratin fibers using an anhydrous dye composition comprising at least one compound of azomethine type comprising two pyrazolopyridine units of formula (I) or (II) and an aqueous composition. The invention also relates to a kit comprising an anhydrous dyeing composition and an aqueous composition. ##STR00001##

A thermal transfer recording sheet includes a base material and, on the base material, a yellow-dye layer containing a yellow dye, a magenta-dye layer containing a magenta dye, and a cyan-dye layer containing a cyan dye. The yellow dye and the cyan dye contain compounds having specific structures.

The invention relates to cationic direct dyes of the formula I (1), wherein m and n are independently from each other 0 or 1, D is an aromatic or a cationic heteroaromatic group, which are further specified, K is an aromatic or heteroaromatic group, E.sub.1 and E.sub.2 are independently from each other CH or N, An is an anion and a is a number from 1 to 6 and R.sub.1 and R.sub.2 are independently from each other and further specified. The compounds show washfastness at hair-dying. ##STR00001##

There are provided a fluorescent compound represented by General Formula (1) and a fluorescently labeled biological substance using the fluorescent compound.

##STR00001##

In the formula, FL indicates an n-valent phosphor moiety, and n is an integer of 1 or more.

R.sup.11 to R.sup.15 represent a hydrogen atom or a substituent. However, at least one combination of the combination of R.sup.11 and R.sup.12 or the combination of R.sup.12 and R.sup.13 is a combination in which one is SO.sub.3.sup.?X.sup.+ and the other is a substituent. X.sup.+ represents a hydrogen ion or a metal ion.