| 摘要 |
Provide is a compound having absorbability in an infrared region, excellent invisibility and robustness. The compound is a squarylium compound represented Formula (1): wherein, R1 and R2 represent an alkyl group, cycloalkyl group, aryl group, or heteroaryl group, which may be substituted by a substituent; R3 and R4 represent a hydrogen atom or alkyl group; X1 and X2 represent an oxygen atom or —NR5—, in which R5 represents a hydrogen atom or alkyl group; Y1, Y2, Y3 and Y4 represent a halogen atom, alkyl group, cycloalkyl group, aryl group, heteroaryl group, arylcarbonyloxy group, or alkylcarbonyloxy group; a plurality of Y1's, Y2's, Y3's, or Y4's may be bonded to form a ring structure, respectively; Y1 and Y2, or Y3 and Y4 may be bonded to form a ring structure; n1 and n4 represent an integer of 0 to 3; and n2 and n3 represent an integer of 0 to 2.
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