A compound represented by Formula (1) or (11) below,

X-A.sup.1-(N═N-A.sup.2).sub.n-N═N-A.sup.3-Y  (1) (in Formula (1), -A.sup.1- and -A.sup.2- each independently represent an unsubstituted or substituted divalent group of an aromatic heterocyclic ring including one or more S atoms wherein atoms constituting the aromatic heterocyclic ring other than a carbon atom are not adjacent to one another, an unsubstituted or substituted divalent group of a benzisothiazole ring, or an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; -A.sup.3- represents an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; —X represents a branched alkyl, alkoxy, or alkylsulfanyl group having 3 or more carbon atoms; —Y represents a monovalent organic group; n represents 1, 2, or 3; when n is 2 or 3, a plurality of -A.sup.2-'s may be identical to or different from one another; and -A.sup.1- and -A.sup.2- do not represent an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring at the same time),

X-A.sup.41-(N═N-A.sup.42).sub.n-N═N-A.sup.43-Y  (11) (in Formula (11), at least one -A.sup.42- represents an unsubstituted or substituted divalent group of an aromatic heterocyclic ring including one or more S atoms; -A.sup.41- and -A.sup.43- each independently represent an unsubstituted or substituted divalent group of an aromatic hydrocarbon ring; —X represents a branched alkyl, alkoxy, or alkylsulfanyl group having 3 or more carbon atoms; —Y represents a monovalent organic group; n represents 1, 2, or 3; and when n is 2 or 3, a plurality of -A.sup.42-'s may be identical to or different from one another).

An azo pigment is provided which can be used as a coloring agent, etc. for use in paints, plastics, synthetic fibers, printing inks, and writing materials or for image recording or image displaying and which has performance of exhibiting high near infrared reflection/transparency, particularly when used as a heat-shielding paint, even in the case where the pigment has a dark color, and as a result, colored articles having the above-described properties are provided, and furthermore an article that is also useful as a printing ink in the security field is provided particularly when the pigment has a dark or black color. Specifically, an azo pigment is provided which is obtained through coupling reaction between a particular azo component and a particular coupling component, which has a plurality of chromophores of an azomethine group and of an azo group within a molecule, and in which the diazo component is a diazotized product of 3-(4-aminophenylimino)-1-oxo-4,5,6,7-tetrachroloisoindoline.

The present invention provides a pigment dispersant: that is capable of remarkably ameliorating fluidity of a liquid product, such as an ink or a paint, which contains particles of a pigment, such as a black azo pigment, in a dispersed state; that can suppress aggregation of piment particles; that prevents occurrence of foreign substances; and that is capable of producing a colored article excellent in optical density. Provided is a pigment dispersant being a compound represented by the following formula (1).

##STR00001##

wherein R.sub.1 and R.sub.2 each independently represent a group obtained by eliminating one hydrogen atom from an amino group of an amine compound containing a basic nitrogen atom, and R.sub.3 and R.sub.4 each independently represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a hydroxy group.

Provided is a black pigment that enables pattern formation of pixel division layer while suppressing generation of development residue. The black pigment comprises (a) a core containing at least one organic black pigment selected from the group consisting of benzodifuranone-based black pigments, perylene-based black pigments, azo-based black pigments, and isomers thereof and (b) a coating layer containing silica and/or a metal oxide and/or a metal hydroxide.

Provided is a black pigment that enables pattern formation of pixel division layer while suppressing generation of development residue. The black pigment comprises (a) a core containing at least one organic black pigment selected from the group consisting of benzodifuranone-based black pigments, perylene-based black pigments, azo-based black pigments, and isomers thereof and (b) a coating layer containing silica and/or a metal oxide and/or a metal hydroxide.

A compound of formula (1) or (11):
X-A.sup.1-(N?N-A.sup.2).sub.n-N?N-A.sup.3-Y(1)
X-A.sup.41-(N?N-A.sup.42).sub.n-N?N-A.sup.43-Y(11), -A.sup.1- and -A.sup.2- being independently a divalent group of an S-containing aromatic heterocyclic ring, with no adjacent non-carbons in the ring, a divalent group of a benzisothiazole ring, or a divalent group of an aromatic hydrocarbon ring, -A.sup.3- being a divalent group of an aromatic hydrocarbon ring, X is a branched alkyl, alkoxy, or alkylsulfanyl group having 3 or more carbon atoms, Y is a monovalent organic group, n is 1, 2, or 3, when n is 2 or 3, a plurality of -A.sup.2-s and/or -A.sup.42-s optionally differing, wherein -A.sup.1- and -A.sup.2- are not both a divalent group of an aromatic hydrocarbon ring, at least one -A.sup.42- is a divalent group of an S-containing aromatic heterocyclic ring, -A.sup.41- and -A.sup.43- are independently a divalent group of an aromatic hydrocarbon ring.

This invention relates to electrophoretic fluid comprising solvents, a highly absorbing dye, and charged particles of different color, and electrophoretic display devices comprising such fluids.

Organic dye for a dye sensitized solar cell (DSSC) comprising at least one substituted pyrrole group. Said organic dye is particularly useful in a dye sensitized photoelectric transformation element which, in its turn, can be used in a dye sensitized solar cell (DSSC).

Disclosed is a mono-azo dichroic dye compound represented by the following Chemical Formula 1, a composition for polarizing plate, a polarizing plate, and an optical device. ##STR00001## In Chemical Formula 1, R.sub.3 represents a substituted or non-substituted heterocyclic group having 1-20 carbon atoms. The mono-azo dichroic dye compound shows excellent dichroic properties, and has excellent heat resistance and photo-resistance, and thus may be used advantageously for a dye-based polarizing plate.