Achiral dicarboxylic acids were coupled with 2 eq. of the free alpha-amino groups of two fully side-chain protected peptide chains while these were still attached to a synthesis resin. Cleavage from the resin with simultaneous side-chain deprotection afforded two assembled peptide chains with free C-terminals. Suitable functionalization of the achiral dicarboxylic acid alternatively permitted continued peptide synthesis in a C to N orientation leading to a final peptide assembly which, after cleavage from the resin, may have multiple N to C and C to N presentation of one or more epitopes.