The preparation of 6-(9-acridinylamino)hexanoic acid DHBT ester and N alpha-Fmoc-N epsilon-(4-nitrophenylsulfonyl)-L-lysine DHBT ester and their application in solid phase peptide synthesis are described. The 9-acridinylamino ligand was shown to confer high DNA affinity, probably by intercalation, to the resulting peptides. The 4-nitrophenylsulfamido ligand furthermore resulted in "photonuclease" activity of some of the modified peptides.