Massarigenin A (1) and papyracillic acids A (2) and B (3) were isolated from the endophytic fungus Microsphaeropsis sp. Their structures were elucidated by multidimensional nuclear magnetic resonance spectroscopy; the structure of massarigenin A (1) was also confirmed by X‐ray crystallography. The absolute configuration of massarigenin A (1) was established by means of circular dichroism (CD) spectroscopy and time‐dependent density functional theory (TDDFT) calculations. The impact of intermolecular hydrogen bonds detected in the crystal packing of 1 on CD spectra measured in the solid state was also investigated. Chirality, 2011. © 2011 Wiley‐Liss, Inc.