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-continued 

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Below, general formula (II) will be described. 

In general formula (II), each ofR$_{21}$, R$_{22 }$and R$_{23 }$indepen› dently represents a hydrogen atom, an alkyl group, a monova› lent aliphatic hydrocarbon ring group, a halogen atom, a cyano group or an alkoxycarbonyl group, provided that R$_{22 }$ may be bonded to Ar$_{2 }$ to thereby form a ring (in particular, preferably a 5- or 6-membered ring), which R$_{22 }$ in this instance is an alkylene group. 

The alkyl group represented by each ofR$_{21}$, R$_{22 }$and R$_{23 }$is an optionally substituted linearor branched alkyl group, pref› erably an optionally substituted alkyl group having 20 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec› butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group or a dodecyl group. An alkyl group having 8 or less carbon atoms is more preferred. An alkyl group having 3 or less carbon atoms is most preferred. 

The alkyl group contained in the alkoxycarbonyl group is preferably the same as the alkyl group mentioned above with respect to R$_{21}$ , R $_{22 }$and R$_{23}$ . 

As the monovalent aliphatic hydrocarbon ring group, there can be mentioned an optionally substituted mono- or polycy› cloalkyl group. An optionally substituted monocyclic monovalent aliphatic hydrocarbon ring group having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group or a cyclohexyl group, is preferred. 

As the halogen atom, there can be mentioned a fluorine atom, a chlorine atom, a bromine atom or an iodine atom. A fluorine atom is especially preferred. 

As preferred substituents that can be introduced in these groups, there can be mentioned a hydroxyl group; a halogen atom (fluorine, chlorine, bromine or iodine); a nitro group; a cyano group; an amido group; a sulfonamido group; any of the alkyl groups mentioned above with respect to R$_{21 }$to R$_{23}$; an alkoxy group, such as a methoxy group, an ethoxy group, a hydroxyethoxy group, a propoxy group, a hydroxypropoxy group or a butoxy group; an alkoxycarbonyl group, such as a methoxycarbonyl group or an ethoxycarbonyl group; an acyl group, such as a formyl group, an acetyl group or a benzoyl group; an acyloxy group, such as an acetoxy group or a butyryloxy group; and a carboxyl group. A hydroxyl group and a halogen atom are especially preferred. 

When R$_{22 }$ is an alkylene group and is bonded to Ar$_{2 }$ to thereby form a ring, the alkylene group is preferably an alky› lene group having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group or an octylene group. An alkylene group having 1 to 4 carbon atoms is more preferred. An alkylene group having 1 or 2 carbon atoms is most preferred. 

In general formula (II), each of R$_{21 }$ and R$_{23 }$ preferably represents a hydrogen atom, an alkyl group or a halogen atom. R$_{22 }$preferably represents a hydrogen atom, an alkyl group, a halogen atom or an alkylene group which forms a ring in cooperation withAr$_{2 }$ 

Ar $_{2 }$represents a bivalent aromatic ring group. A substituent may be introduced in the bivalent aromatic ring group. As preferred examples of the bivalent aromatic ring group, there can be mentioned, for example, an arylene group having 6 to 18 carbon atoms, such as a phenylene group, a tolylene group or a naphthylene group, and a bivalent aromatic ring group containing a heteroring, such as thiophene, furan, pyrrole, benzothiophene, benzofuran, benzopyrrole, triazine, imida› zole, benzimidazole, triazole, thiadiazole or triazole. 

X$_{21 }$ represents ---0-, -S-, --CO-, -SO$_{2}$-, -NR- (R represents a hydrogen atom or an alkyl group), a bivalent nitrogenous nonaromatic heterocyclic group or a group composed of a combination of these. 

Particular examples of the -NR- and bivalent nitrog› enous nonaromatic heterocyclic group represented by X$_{21 }$are the same as mentioned above in connection with X$_{11}$. Pre› ferred examples are also the same. 

Preferably, X$_{21 }$ is ---0-, -S-, --CO-, -SO$_{2}$ - or a group composed of a combination of these. ---0-, ---OCO- and ---OSO$_{2}$ - are especially preferred. 

X$_{22 }$ represents a single bond, -0-, -S-, --CO-, -SO$_{2}$ -, -NR-(Rrepresents a hydrogen atom or an alkyl group), a bivalent nitrogenous nonaromatic heterocyclic group or a group composed of a combination of these. 

Particular examples of the -NR- and bivalent nitrog› enous nonaromatic heterocyclic group represented by X$_{22 }$are the same as mentioned above in connection with X$_{11}$. Pre› ferred examples are also the same. 

Preferably, X$_{22 }$is ---0-, -S-, --CO-, -SO$_{2}$ - or a group composed of a combination of these. ---0-, ---OCO-and -OSO$_{2}$ - are especially preferred. 

L$_{21 }$ represents a single bond, an alkylene group, an alk- enylene group, a bivalent aliphatic hydrocarbon ring group, a bivalent aromatic ring group or a group composed of a com› bination of two or more of these, provided that in the group composed of a combination, two or more groups combined together may be identical to or different from each other and may be linked to each other through, as a connecting group, ---0-, -S-, -CO-, -SO$_{2}$ -, -NR- (R represents a hydrogen atom or an alkyl group), a bivalent nitrogenous nonaromatic heterocyclic group or a group composed of a combination of these. 

Particular examples of the alkylene group, alkenylene group and bivalent aliphatic hydrocarbon ring group repre› sented by L$_{21 }$are the same as the above preferred examples of the alkylene group, alkenylene group and bivalent aliphatic hydrocarbon ring group represented by L$_{11 }$ of general for› mula (I). 

As the bivalent aromatic ring group represented by L$_{21}$, there can be mentioned, for example, an optionally substi› tuted arylene group having 6 to 14 carbon atoms, such as a phenylene group, a tolylene group or a naphthylene group, or an optionally substituted bivalent aromatic ring group con› taining a heteroring, such as thiophene, furan, pyrrole, ben- 

