High-melting-point polymers with heterocyclic backbone units were synthesized from common amino acids. Acids were first converted to methyl ester salts and then were dimerized to form diketopiperazines, which were polymerized in solution. Aspartic acid, serine, lysine, glycine, and tyrosine were used as starting materials for the diketopiperazines. Aromatic and aliphatic comonomers were used. Thus, we demonstrate the technical feasibility of producing strong, durable resins from abundant domestic resources. These resins show great potential for high-performance polymers for use in films, fibers, and composites.