A composition comprising (a) one or more aromatic ether compounds selected from anisole, ethyl phenyl ether, propyl phenyl ether, butyl phenyl ether, methylanisole, dimethylanisole, ethylanisole, methylethylanisole, diethylanisole, propylanisole, butylanisole, pentylanisole, hexylanisole, heptylanisole, octylanisole, methyl naphthyl ether, and diphenyl ether; (b) one or more compounds having boiling points equal to or higher than 200°C and having melting points equal to or lower than 25°C and being chosen from n-dodecane, n-tridecane, n-tetradecane, 1-nonanol, n-decanol, 2-decanol, n-undecanol, isodecanol, n-tetradecanol, diethylene glycol, triethylene glycol, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monobenzyl ether, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, n-octyl acetate, diethyl succinate, acetamide, thiodiglycol, bicyclohexyl, 2-(1-cyclohexenyl)cyclohexanone, γ-butyrolactone, propylene carbonate, δ-valerolactone, isophorone, N-methylpyrrolidone, 2-pyrrolidone, sulfolane, n-pentylbenzene, n-hexylbenzene, n- heptylbenzene, n-octylbenzene, n-nonalbenzene, n-decylbenzene, 1,3-di-isopropylbenzene, 1,4-di-isopropylbenzene, cyclohexylbenzene, tetralin, biphenyl, m-cresol, p-cresol, p-ethylphenol, 4-methoxyphenol, o-n-propylphenol, o-isopropylphenol, o-s-butylphenol, o-t-butylphenol, m-t-butylphenol, p-t-butylphenol, benzyl alcohol, benzoic acid, phenylacetic acid, quinoline and imidazole; and (c) one or more polymers that transport charges or emit light in a solid state having weight average molecular weights of 1.0 × 10 3 to 1.0 × 10 7 relative to polystyrene, which polymer comprises any one of repeat units of formulae to: wherein Ar 1, Ar 2, Ar 3 and Ar 4 each independently represent an arylene group or a divalent heterocyclic group; Ar 5, Ar 6 and Ar 7 each independently represent an aryl group or a monovalent heterocyclic group; Ar 1, Ar 2, Ar 3, Ar 4, Ar 5, Ar 6 and Ar 7 may have a substituent; and x and y each independently represent 0 or a positive integer; wherein ring A and ring B each independently represent an aromatic hydrocarbon ring that may have a substituent; two bonds are respectively present on the ring A and/or the ring B; and R 1 and R 2 each independently represent a substituent; wherein ring A and ring B are as defined above; two bonds are respectively present on the ring A and/or ring B; Z represents -O-, -S-, -S (=O)-, -S (=O) (=O)-, -N (R 3)-, -Si(R 3)(R 4)-, -P(=O)(R 3)-, -P(R 3)-, -B(R 3)-, -C(R 3)(R 4)-O-, -C(R 3)=N- or -Se-; and R 3 and R 4 each independently represent a substituent; wherein R 5 represents a substituent; n represents an integer of 0 to 4; and when a plurality of R 5 are present, they may be the same or different; wherein R 6 and R 7 represent a substituent; o and p each independently represent an integer of 0 to 3; and when a plurality of R 6 and R 7 are present, they may be the same or different; wherein R 8, R 9, R 10, R 11 represent a substituent; q and r each independently represent an integer of 0 to 4; and when a plurality of R 8 and R 9 are present, they may be the same or different; wherein R 12 represents a substituent; u represents an integer of 0 to 2; Ar 8 and Ar 9 each independently represent an arylene group, divalent heterocyclic group, or divalent group including a metal complex structure; s and t each independently represent 0 or 1; X 1 represents -O-, -S-, -S (=O) -, -SO 2 -, -Se-, or -Te-; and when a plurality of R 12 are present, they may be the same or different; wherein Ar 10 and Ar 11 each independently represent an arylene group, divalent heterocyclic group, or divalent group including a metal complex structure; v and w each independently represent 0 or 1; X 2 represents -O-, -S-, -S(=O)-, -S(=O)(=O)-, -Se-, -Te-, NR 14 -, or -SiR 15 R 16 -; said composition being in a liquid state at 25°C and having a viscosity of 1 to 20 mPa·s; the weight of said polymers based on a total weight of the composition being 0.1 to 5.0 wt%.