The work of this dissertation is the culmination of five years of research in the field of marine natural products chemistry. It involves the investigation of halogenated constituents isolated from Indo-Pacific marine sponges associated with cyanobacterial symtionts. The primary goal in the UCSC research group is to seek out novel and interesting secondary metabolites produced by marine organisms, specifically marine sponges, isolate and elucidate their chemical structures and determine their biological activity against cancer.