Chloraserrtone A, a Sesquiterpenoid Dimer from <i>Chloranthus serratus</i> BaiBai YeShao-Xia YangDe-Po ZhuLong-Ping TangGui-Hua ChenYun-Yun LiGeorge Qian ZhaoZhi-Min 2019 Chloraserrtone A (<b>1</b>), a new sesquiterpenoid dimer with two lindenane-type sesquiterpenoid monomers bridged by two six-membered rings, was obtained from <i>Chloranthus serratus</i>. A combination of UV, IR, NMR, HRESIMS, and X-ray diffraction data were used to elucidate the structure of <b>1</b>. Compound <b>1</b> represents the first lindenane-type sesquiterpenoid dimer with extremely unique C-15–C-15′, C-4–C-6′, and C-6–C-11′ linkages to form two six-membered rings between the monomeric units. A plausible biosynthesis toward chloraserrtone A is proposed. This new compound (<b>1</b>), together with the known lindenane dimers (<b>2</b>–<b>11</b>), were assessed for their inhibitory effects on lipopolysaccharide-induced NO production in RAW264.7 cells. Compound <b>6</b> showed activity with an IC<sub>50</sub> value of 3.7 μM.