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benzofuran residue, and benzothiophene residue. In a case where the arylsulfonium compound has two or more aryl groups, the two or more aryl groups may be the same as or different from each other. 

[0315] An alkyl group or a cycloalkyl group which the arylsulfonium compound has according to necessity is pref› erably a linear or branched alkyl group having 1 to 15 carbon atoms or a cycloalkyl group having 3 to 15 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, a sec-butyl group, at-butyl group, a cyclopropyl group, a cyclobutyl group, and a cyclo› hexyl group. 

[0316] The aryl group, the alkyl group, and the cycloalkyl group represented by each ofR$_{201 }$to R$_{203 }$may have an alkyl group (having 1 to 15 carbon atoms, for example), a cycloalkyl group (having 3 to 15 carbon atoms, for example), an aryl group (having 6 to 14 carbon atoms, for example), an alkoxy group (having 1 to 15 carbon atoms, for example), a halogen atom, a hydroxyl group, or a phenylthio group, as a substituent. 

[ 0317] Next, the compound (ZI-2) will be described. 

[0318] The compound (ZI-2) is a compound in which each ofR$_{201 }$to R$_{203 }$in Formula (ZI) independently represents an organic group not having an aromatic ring. The aromatic ring herein also includes an aromatic ring containing a hetero atom. 

[0319] The organic group not containing an aromatic ring represented by each of R$_{201 }$ to R$_{203 }$ generally has 1 to 30 carbon atoms, and preferably has 1 to 20 carbon atoms. 

[0320] Each ofR$_{201 }$to R$_{203 }$independently preferably rep› resents an alkyl group, a cycloalkyl group, an ally! group, or a vinyl group, more preferably a linear or branched 2-oxoalkyl group, a 2-oxocycloalkyl group, or an alkoxycar› bonylmethyl group, and particularly preferably a linear or branched 2-oxoalkyl group. 

[0321] Preferable examples of the alkyl group and the cycloalkyl group represented by each ofR$_{201 }$to R$_{203 }$include a linear or branched alkyl group having 1 to 10 carbon atoms (for example, a methyl group, an ethyl group, a propyl group, a butyl group, or a pentyl group) and a cycloalkyl group having 3 to 10 carbon atoms (a cyclopentyl group, a cyclo› hexyl group, or a norbomyl group). 

[0322] Each ofR$_{201 }$to R$_{203 }$may be further substituted with a halogen atom, an alkoxy group (which has 1 to 5 carbon atoms, for example), a hydroxyl group, a cyano group, or a nitro group. 

[0323] Next, the compound (ZI-3) will be described. 

[0324] The compound (ZI-3) is a compound which is rep› resented by the following General Formula (ZI-3) and has a phenacylsulfonium salt structure. 

<img src='content_image/931391.jpg'>

[0325] In General Formula (ZI-3), each ofR$_{1}$c to R$_{5}$c inde› pendently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy 

(ZI-3) 

group, an alkoxycarbonyl group, an alkylcarbonyloxy group, a cycloalkylcarbonyloxy group, a halogen atom, a hydroxyl group, a nitro group, an alkylthio group, or an arylthio group. 

[0326] Each of R 6 c and R$_{7}$c independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, a cyano group, or an aryl group. 

[0327] Each of Rx and RY independently represents an alkyl group, a cycloalkyl group, a 2-oxoalkyl group, a 2-oxocy› cloalkyl group, an alkoxycarbonylalkyl group, an ally! group, or a vinyl group. 

[0328] Any two or more ofRlc to Rsc, Rsc and R6c, R6c and R$_{7}$c, R$_{5}$c and Rx, and Rx and RY may be respectively bonded to each other to form a ring structure, and the ring structure may include an oxygen atom, a sulfur atom, a ketone group, an ester bond, or an amide bond. 

[0329] Examples of the ring structure include an aromatic or non-aromatic hydrocarbon ring, an aromatic or non-aro› matic heterocycle, or a polycyclic condensed ring formed by combination of two or more of these rings. Examples of the ring structure include 3- to IO-membered rings, and among these, 4- to 8-membered rings are preferable, and 5- or 6-membered rings are more preferable. 

[0330] Examples of the group formed by bonding of any two or more ofR$_{1}$c to R$_{5}$c, R 6 c and R$_{7}$c, or Rx and RY to each other include a butylene group and a pentylene group. 

[0331] As the group that R$_{5}$c and R 6 c, and R$_{5}$c and Rx respectively form by bonding to each other, a single bond or an alkylene group is preferable, and examples of the alkylene group include a methylene group and an ethylene group. 

[0332] zc- represents a non-nucleophilic anion, and as zc-, the same as the non-nucleophilic anion represented by z- in General Formula (ZI) can be exemplified. 

[0333] Specific examples of the alkoxy group in the alkoxy› carbonyl group represented by each ofR$_{1}$c to R$_{5}$c are the same as the specific examples of the alkoxy group represented by each ofR$_{1}$c to R$_{5}$c described above. 

[0334] Specific examples of the alkyl group in the alkylcar› bonyloxy group and the alkylthio group represented by each ofR$_{1}$c to R$_{5}$c are the same as the specific examples of the alkyl group represented by each ofR$_{1}$c to R$_{5}$c described above. 

[0335] Specific examples of the cycloalkyl group in the cycloalkylcarbonyloxy group represented by each of R$_{1}$c to R$_{5}$c are the same as the specific examples of the cycloalkyl group represented by each ofR$_{1}$c to R$_{5}$c described above. 

[0336] Specific examples of the aryl group in the aryloxy group and the arylthio group represented by each ofR$_{1}$c to R$_{5}$c are the same as the specific examples of the aryl group rep› resented by each ofR$_{1}$c to R$_{5}$c described above. 

[0337] Examples of the cation in the compound (ZI-2) or (ZI-3) in the present invention include the cations described in paragraphs "0036" and later ofUS2012/0076996A. 

[0338] Next, the compound (ZI-4) will be described. 

[0339] The compound (ZI-4) is represented by the follow› ing General Formula (ZI-4). 

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(ZI-4) 

