As part of our ongoing chemical investigation of biologically active metabolites from marine-derived fungi, four new polyphenols containing both phenolic bisabolane and diphenyl ether units, expansols C–F (1–4), and one new diphenyl ether derivative, 3-O-methyldiorcinol (5), as well as twelve known compounds (6–17), were isolated from Penicillium expansum 091006 endogenous with the mangrove plant Excoecaria agallocha (Euphorbiaceae). The structures of the new metabolites were determined on the basis of NMR and mass spectroscopy. Among them, expansols C (1) and E (3) exhibited weak cytotoxicity against the HL-60 cell lines with IC₅₀ values of 18.2 and 20.8 µM, respectively. The results showed that diphenyl ether substituted phenolic bisabolanes with a Δ⁷ double bond in the side chain are slightly less cytotoxic to HL-60 cell lines than the 7-OH or 7-OCH₃ derivatives. ^* These authors contributed equally to this work.