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).

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).

Provided is a composition which can be used for formation of an optical film having high quality and a high dichroic ratio even after the composition is stored for a predetermined period of time. The composition includes a compound represented by the general formula (A) and a compound represented by the general formula (B), wherein R.sup.1a in the general formula (A) and R.sup.1b in the general formula (B) are mutually different groups.

R.sup.1a—Ar.sup.1a—N═N—Ar.sup.2a—N═N—Ar.sup.3a—R.sup.10a   (A)

R.sup.1b—Ar.sup.1b—N═N—Ar.sup.2b—N═N—Ar.sup.3b—R.sup.10a   (B)

Provided is an optical film which has a maximum absorption at a wavelength in the range of 600 to 680 nm, has a high dichroic ratio, and is excellent in light resistance. The optical film includes: a polymer of a polymerizable liquid crystal compound; and a compound represented by the following general formula (1).

##STR00001##

A compound having a maximum absorption in a wavelength range of 350 nm to 550 nm that functions as a dichroic dye is provided. In particular, a compound represented by formula (1) is provided. In the compound represented by formula (1), R.sup.1 represents a hydrogen atom or the like; R.sup.2 represents an acyl group having 1 to 20 carbon atoms or the like; R.sup.3 represents a hydrogen atom or the like; and Y represents a group of formula (Y1). In the group of formula (Y1), * represents a bonding site with N, or a group of formula (Y2); and in the group of formula (Y2), * represents a bonding site with N; P.sup.1 and P.sup.2 each independently represent —S— or the like; and Q.sup.1 and Q.sup.2 each independently represent ═N— or the like.

##STR00001##

An azo compound excellent in solubility in solvent and having a high absorbance coefficient is disclosed, as well as an ink containing the azo compound. Such an ink contains a solvent having a relative permittivity at 22° C. and at a measurement frequency of 1 kHz of 3 or less and having a solubility in water at 25° C. of 20 mg/L or less, and an azo compound.

An azo compound excellent in solubility in solvent and having a high absorbance coefficient is disclosed, as well as an ink containing the azo compound. Such an ink contains a solvent having a relative permittivity at 22° C. and at a measurement frequency of 1 kHz of 3 or less and having a solubility in water at 25° C. of 20 mg/L or less, and an azo compound.

Dichroic azo-azomethine dyes of formula (A) or (B), wherein Ar.sup.1 to Ar.sup.10 are specific (hetero)aromatic moieties and L is a linking group, as defined in the present claims, a dichroic dye mixture comprising said azo-azomethine dyes and a process for preparing the dyes are provided. The dyes are well suited for combination with liquid crystal material for use, inter alia, in a light absorption anisotropic element, for example, in a switchable optical device or an optically anisotropic film.

##STR00001##

Dichroic azo-azomethine dyes of formula (A) or (B), wherein Ar.sup.1 to Ar.sup.10 are specific (hetero)aromatic moieties and L is a linking group, as defined in the present claims, a dichroic dye mixture comprising said azo-azomethine dyes and a process for preparing the dyes are provided. The dyes are well suited for combination with liquid crystal material for use, inter alia, in a light absorption anisotropic element, for example, in a switchable optical device or an optically anisotropic film.

##STR00001##

A composition is provided which contains a compound represented by Formula (1) below and a polymerizable smectic liquid crystal compound: ##STR00001##
In Formula (1), R.sup.1 represents a hydrogen atom or a C1-C20 alkyl group; R.sup.2 through R.sup.4 each independently represent a C1-C4 alkyl group; n, p, and q are each independently an integer of 0 to 2; and R.sup.5 is (i) a nitrogen-containing saturated heterocyclic group which is a 6-membered ring and in which N is bonded to a phenylene group, or (ii) a group in which N is bonded to at least one C1-C10 alkyl group.