an electrode active material for a lithium secondary battery using a heterocyclic compound and a lithium secondary battery including the same are provided . the heterocyclic compound , which is useful as a cathode or anode active material , includes a six - membered ring and a five - membered ring containing one or more elements selected from the group consisting of nitrogen , oxygen and sulfur , and the heterocyclic compound is configured such that two pairs of carbons which form double bonds with nitrogen atoms contain a functional group linked by a single bond , thus exhibiting redox activity .