Synthesis of mixed imine–amine pyrrolobenzodiazepine (PBD) dimers that are comprised of DC-81 and secondary amine (N10) of DC-81 subunits tethered to their C8 positions through alkanedioxy linkers (comprised of three and five carbons) is described. These noncross- linking unsymmetrical molecules exhibit significant DNA minor groove binding ability and one of them 5b linked through the pentanedioxy chain exhibits efficient DNA binding ...