A bioactivity-directed fractionation of the extracts of the Malaysian plant Garcinia pavifolia and a phytochemical study of G. griffithii led to the discovery of griffipavixanthone (1), a novel cytotoxic bixanthone with cyclized prenyl groups providing the xanthone-xanthone linkage. Spectroscopic data and preparation of methylated derivatives allowed for the complete structural elucidation of 1.