<jats:title>Abstract</jats:title><jats:p>Four new phenylspirodrimane‐type dimers, namely chartarlactams Q−T, along with stachyin B were isolated from the fermentation broth of a sponge‐derived fungus <jats:italic>Stachybotrys chartarum</jats:italic> WGC‐25 C‐6. Chartarlactams Q−T were structurally featured by the dimerization of two units of phenylspirodrimane linked by a C−N bond. Their structures were determined on the basis of extensive spectroscopic analysis, while quantum ECD calculation and modified Mosher's method were used for the assignment of absolute configurations. Chartarlactams Q−S and stachyin B showed moderate inhibition against bacterial pathogen <jats:italic>Staphylococcus aureus</jats:italic> with MIC values ranging from 4 μg/mL to 16 μg/mL, and chartarlactam T exhibited significant inhibition toward ZIKV virus.