According to one embodiment, there is provided a compound represented by Formula (1): where Cu+ represents a copper ion, each of R1 and R2 represents a linear, branched or cyclic alkyl group or an aromatic cyclic group which may have a substituent, each of R3, R4, R5 and R6 represents a halogen atom, a cyano group, a nitro group, a linear, branched or cyclic alkyl group or H, and X- represents a counter ion where X is selected from the group consisting of F, Cl, Br, I, BF4, PF6, CH3CO2, CF3CO2, CF3SO3 and ClO4.