Two new cyclic heptapeptides (1.2) have been isolated from the ascidian Lissoclinum bisrrmm, and their structures determined by a combination of spectmscopic techniques. including a natural abundance two-dimensional tH( t%J,lH)-HMQC-TOCSY experiment which was pivotal to assigning and identifying the amino acid residues. tH( tsC)-HMBC and [tH-tH]-ROESY experiments provided the correlations necessary to sequence the peptides. In both peptides, the lle-Pro amide bonds adopt cis configurations.