Structural variants of the marine sponge metabolite ilimaquinone, with comparable biological activity, have been prepared. These analogs, as well as related natural products, were screened for their effects on the Golgi apparatus through a novel, non-radioisotope-based secretion assay. The assay has identified a variant of ilimaquinone that contains a versatile linker group yet retains the natural product's cellular activity. This functional ilimaquinone analog will be a valuable tool for studying intracellular protein trafficking.