Four new bis(indole) alkaloids, rhopaladins A similar to D (1 similar to 4), have been isolated from the Okinawan marine tunicate Rhopalaea sp. and the structures were elucidated on the basis of spectroscopic data. The presence of two rotational isomers (3a and 3b) of 3 was deduced from NOESY data and molecular calculation using Macromodel program. (C) 1998 Elsevier Science Ltd. All rights reserved.