A composition comprising a phosphorescent compound, and a compound having a structure containing three or more repeating units having a dipole moment dimension of 1.0 Debye or more connected in series, wherein, based on the total number of dimer structures composed of any two repeating units connected in series contained in the above-described structure, the proportion of the number of dimer structures in which the dimension D2 of the dipole moment of the dimer structure, the dimension D1a of the dipole moment of the first repeating unit constituting the dimer structure and the dimension D1b of the dipole moment of the second repeating unit constituting the dimer structure satisfy a relation represented by the following formula (A): D1a