Chemical study of a previously undescribed fungus, Talaromyces thailandiasis, furnished the two new merodrimanes thailandolides A (1) and B (2), an O-methylated derivative (3) of the aromatic fragment incorporated in thailandolide B, and three known closely related 1(3H)-isobenzofuran derivatives, penisimplicissin (4a), vermistatin (4b), and hydroxydihydrovermistatin (4c). Structures were established by spectroscopic measurements and confirmed by X-ray analyses of compounds 1 and 4b. The unusual peptide analogue N-benzoylphenylalanyl-N-benzoylphenyl alaninate (5) isolated earlier from a higher plant was also found.