TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The ionic compound has a structure of formula: (M(power)(m'+))a(X'(power)(n'-))b.M(power)(m'+)=metal cation, preferably alkali metal cation or alkaline earth metal cation;X'(power)(n'-)=anion;anda,b=1 or more.The metal nanostructure is a metal nanostructure of group 11 metal, preferably silver nanostructure. The peak of one or more atoms existing in the metal complex calculated by X-ray photoelectron spectroscopy includes a peak derived from the atom of conjugated compound having a molecular weight of 200 or more. The orbital energy of highest occupied molecular orbital (HOMO) of the conjugated compound having a molecular weight of 200 or more is less than -4.5 eV, and the orbital energy of lowest unoccupied molecular orbital is more than -3.5 eV.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compound: The conjugated compound having a molecular weight of 200 or more is an aromatic compound having a group containing a heteroatom. The group containing heteroatom is mercapto group, mercapto carbonyl group, mercapto thiocarbonyl group, optionally substituted hydrocarbylthio group, optionally substituted hydrocarbyl thiocarbonyl group, optionally substituted hydrocarbyl dithio group, hydroxyl group, optionally substituted hydrocarbyloxy group, carboxyl group, optionally substituted dihydrocarbylamino group, optionally substituted hydrocarbylcarbonyl group, cyano group, amino group, optionally substituted hydrocarbylamino group, phosphino group, optionally substituted hydrocarbyl phosphino group, -P(=O)(OH)2, sulfo group, monovalent heterocyclic group, halo, formyl group, optionally substituted hydrocarbyloxycarbonyl group, optionally substituted hydrocarbyl carbonyloxy group, nitro group, -OP(=O)(OH)2, carbamoyl group, optionally substituted hydrocarbyl carbamoyl group, optionally substituted dihydrocarbyl carbamoyl group, -C(=S)NR2, -B(OH)2, -BR2, boric acid ester residue, -Si(OR)3, optionally substituted hydrocarbyl sulfo group, optionally substituted hydrocarbyl sulfonyl group, sulfino group, optionally substituted hydrocarbyl sulfino group, -NRC(=O)OR, -NRC(=O)SR, -NRC(=S)OR, -NRC(=S)SR, -OC(=O)NR2, -SC(=O)NR2, -OC(=S)NR2, -SC(=S)NR2, -NRC(=O)NR2, and/or -NRC(=S)NR2, or hydrocarbyl group having 2 or more ether bonds, hydrocarbyl group having 2 or more ester bonds, hydrocarbyl group having 2 or more amide bonds, -SM, -C(=O)SM, -CS2M, -OM, -CO2M, -NM2, -NHM, -NRM, -PO3M, -OP(=O)(OM)2, -P(=O)(OM)2, -C(=O)NM2, -C(=O)NHM, -C(=O)NRM, -C(=S)NHM, -C(=S)NRM, -C(=S)NM2, -B(OM)2, -BR3M, -B(OR)3M, -SO3M, -SO2M, -NRC(=O)OM, -NRC(=O)SM, -NRC(=S)OM, -NRC(=S)SM, -OC(=O)NM2, -OC(=O)NRM, -OC(=S)NM2, -OC(=S)NRM, -SC(=O)NM2, -SC(=O)NRM, -SC(=S)NM2, -SC(=S)NRM, -NRC(=O)NM2, -NRC(=O)NRM, -NRC(=S)NM2, -NRC(=S)NRM, -NR3M', -OR3M', -OR2M', -SR2M', -IRM', and/or monovalent heterocyclic group having cationized nitrogen atom in a heterocyclic ring.R=H or optionally substituted hydrocarbyl;M=metal cation or optionally substituted ammonium cation;andM'=anion.The conjugated compound having a molecular weight of 200 or more has repeating units of formula: -Ar1-(-R1-(-X1)m1)n1 or of formula (I).Ar1=n1-valent aromatic group;R1=direct bond or m1-valent group;X1,X2=group containing heteroatom;m1,n1,m,n=1 or more;Ar2=n-valent aromatic group;andR2=direct bond or m-valent group.Preferably, the conjugated compound having a molecular weight of 200 or more is a high-molecular compound having repeating units chosen from 233 repeating units e.g. repeating units of formulae (II)-(XI).