The first chemical study of the marine sponge Callyspongia cf. californica widely distributed along the coasts of the Tropical Eastern Pacific led to the identification of a new family of amphiphilic derivatives called callyspongidic acids. The four isolated metabolites 1-4 feature a hydrophilic diacid end opposed to both an aromatic moiety and a long alkyl chain. They were evaluated against a panel of pathogenic microbes and seven tumoral cell lines, displaying moderate inhibitory properties against the A2058 melanoma cell line with an IC50 of 3.2 μM for callyspongidic acid C13:0 (2).