Solid-phase peptide synthesis (SPPS) yields well-defined polyamides of repeat unit NH-Z-CO bur requires protected derivatives and deprotection steps. Polyamides of repeat unit NH-Y-NH-CO-X-CO (e.g., Nylon 66) are made by polymerizing diacids with diamines, but the absence of protecting groups leads to heterogeneity of chain length. We have produced a new class of polymers by automated solid-phase synthesis without protecting groups: polyamide chains NH-Y-NH-CO-X-CO containing a precise number of monomer units where X and Y can be varied independently at each step. Dimers and multimeric molecules which display phage-derived binding peptides in a synthetic construction were easily assembled with these precision length polyamide chains, which can usefully replace polypeptides and poly(ethylene glycol) as linkers.