The development of a highly efficient methodology for solid-phase synthesis of para- and meta-arylopeptoids (oligomeric N-substituted aminomethyl benzamides) with free acids or free amides at the C-terminus is described. The arylopeptoids were synthesised by means of a convenient submonomer protocol in which the arylopeptoid residues were created in an iterative manner on the growing chain using an acylation–substitution cycle. The uronium salt COMU was found to be the most efficient reagent for ensuring fast and clean couplings of the benzoic acid building blocks.