Abstract: From the marine sponge Rhaphisia pallida Ridley, collected from the South Chinasea, two pure compounds have been obtained.Avariety of spectroscopic techniques such asUV, IR, EIMS, FABMS, 1D NMR, ¹H-¹H COSY, ¹H-¹³C COSY NMR, have been appliedin the structural elucidation of these two compounds.Compounds ⅠandⅡare very inter-esting in having a ten-membered heterocyclic ring, combining a urea unit and a diacylimidemoiety.This is the first report of such novel structure-

Key words: Marine sponge, Rhaphisia pallida, Ten-membered heterocyclic compound