Abstract: The invention provides a method for making a combinatorial library of cyclic compounds, such as Holliday junction-trapping compounds, comprising the steps of (a) obtaining a plurality of trimers according to the generic structure X1-X2-X3, wherein X1, X2 and X3 can be independently any naturally or nonnaturally occurring amino acids or peptidomimetics thereof; (b) optionally coupling a spacer S to the trimer at either end; (c) cyclizing two trimers or trimer-spacer conjugates in a head-to-tail orientation; thereby obtaining a combinatorial library of compounds, wherein the library does not include an unmodifed or naturally occurring Holliday Junction-trapping compounds. The invention additionally provides methods macrocyclic compounds that are synergimycin derivatives.