Constituents of an EtOH extract of the stem bark of Calophyllum panciflorum A. C. SMITH (Guttiferae) collected in Central Province of Papua New Guinea were studied. A novel dibenzofuran named calophyfuran (1) and two new xanthones named pancixanthone-A (3) and pancixanthone-B (4), respectively, were isolated as well as four kinds of known xanthones, and their structures were elucidated by spectrometric methods. Among these components, calophyfuran (1) is the first example of dibenzofuran derivatives having a five-carbon unit (prenyl) as a substituent to be found in nature.