TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The metal nanostructure is a metal nanostructure of group 11 metal, preferably silver nanostructure.    TECHNOLOGY FOCUS - POLYMERS - Preferred Compound: The conjugated compound is an aromatic compound having a group containing a heteroatom. The group containing heteroatom is a monovalent group chosen from mercapto group, mercaptocarbonyl group, mercaptothiocarbonyl group, optionally substituted hydrocarbylthio group, optionally substituted hydrocarbyl thiocarbonyl group, optionally substituted hydrocarbyl dithio group, hydroxyl group, optionally substituted hydrocarbyloxy group, carboxyl group, hydrocarbyl carbonyl group, cyano group, optionally substituted amino group, (optionally substituted hydrocarbyl)amino group, amino(optionally substituted dihydrocarbyl), phosphino group, phosphino(optionally substituted hydrocarbyl), (optionally substituted dihydrocarbyl)phosphino group (-P(=O)(OH)2), sulfo group, heterocyclic group, halogen atom, formyl group, optionally substituted hydrocarbyl oxycarbonyl group, hydrocarbyl carbonyloxy group, optionally substituted nitro group, -OP(=O)(OH)2, phosphono group, carbamoyl group, optionally substituted hydrocarbyl carbamoyl group, carbamoyl(optionally substituted dihydrocarbyl), -C(=S)NR2, -B(OH)2, -BR2, boric-acid ester group, -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 -NRC(=S)NR2, or a monovalent group chosen from 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(OR3)M, -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', -PR3M', -OR2M', -SR2M', -IRM', and heterocyclic group having cationized nitrogen atom in heterocyclic ring.R=H or optionally substituted hydrocarbyl;M=metal cation or ammonium cation which may be substituted;andM'=anion.The conjugated compound is a high-molecular compound having repeating unit chosen from 233 units e.g. repeating units of formulae (III), (IV), (V), (VI) and (VII). When the peak position of one or more atoms existing in the complex calculated by X-ray photoelectron spectroscopy is based on the peak position of Ag3d, the peak derived from the conjugated compound is detected in addition to the peak position of the atom existing inside the metal nanostructure precursor. The highest occupied molecular orbital (HOMO) level of the conjugated compound is less than -4.5 eV, which is the value of ionization potential calculated by optoelectronic spectroscope in air. The lowest unoccupied molecular orbital (LUMO) level of the conjugated compound is more than -3.5 eV, which is the ionization potential calculated by the optoelectronic spectroscope of the conjugated compound, and the value calculated from the level difference of HOMO and LUMO calculated by the measurement of UV, visible and a near-infrared spectrophotometer. EXAMPLE - A silver nanostructure (40 mg) was added to ethanol solution (20 ml) of 6-(4-bromophenyl)-1,3,5-triazine-2,4-dithiol and dispersed by ultrasonic waves. The mixture was centrifuged and supernatant was removed. Ethanol solution (20 ml) of 6-(4-bromophenyl)-1,3,5-triazine-2,4-dithiol was added to the residue, dispersed, stirred and centrifuged. The supernatant was removed. The operation was repeated 5 times. Thus, a metal composite was obtained.