Provided herein are benzopyrimido-pyrrolo-oxazine-dione (BPO) compounds and pyrimido-pyrrolo-quinoxalinedione (PPQ) compounds, and compositions comprising these compounds, that inhibit cystic fibrosis transmembrane conductance regulator (CFTR) mediated ion transport and that are useful for treating diseases and disorders associated with aberrantly increased CFTR chloride channel activity, such as polycystic kidney disease and secretory diarrheas. The compounds and compositions comprising the compounds described herein may be used for inhibiting expansion or preventing formation of cysts in persons who have polycystic kidney disease.