A secondary battery and capacitor includes as an active material of an electrode a compound having a trimer structure comprising three structure units of one or more kind of indole compounds selected from indole and indole derivatives and a condensed polycyclic structure having a six-membered ring composed of atoms of the second and the third position of the each three structure units, wherein the active material comprises as the compound a first compound having a trimer structure wherein any bonds between the structure units are formed among the second position of one structure unit and the third position of the other structure unit and a second compound having a trimer structure comprising a bond formed among the second position of one structure unit and the second position of the other structure unit, and a proton is utilized as a charge carrier of the first compound and the second compound.