Triphyophyllum peltatum (Hutch. et Dalz.) Airy-Shaw is a West African liana belonging to the Dioncophyllaceae — the only plant family besides the Ancistrocladaceae reported to produce naphthylisoquinoline alkaloids. Its folk medicine use warrants chemical and pharmacological investigation. Previously, a series of naphthylisoquinoline alkaloids of three types (7,1'-type dioncophylline A, 7,6'-type dioncophylline B, 5,1'-type dioncophylline C) were isolated from its roots. This paper describes the first isolation and structure elucidation of an alkaloid from T. peltatum leaves. Only dioncophylline B occurs in both roots and leaves; other leaf alkaloids are new. A fully aromatic naphthylisoquinoline 3 (m.p. 177—179°C, [α]5: 00 (c 0.5, CHCl3)) with a "conventional" 7,1'-coupling type is structurally remarkable as the first in this class with an additional methoxy group at C-4 (not from polyketide-type oxygenation). The biaryl axis configuration is under investigation. This new alkaloid demonstrates T. peltatum can broadly vary the naphthylisoquinoline framework via regio- and stereoselective coupling site manipulation, axis stereochemistry, and hydrogenation/oxygenation degrees, while avoiding C-6 oxygen function or C-3 S-configuration unlike Ancistrocladus plants. Ancistrocladus abbreviatus Airy-Shaw is a tropical liana/shrub of the monogeneric Ancistrocladaceae, widely used in folk medicine. It produces naphthylisoquinoline alkaloids with varying coupling sites (e.g., ancistrocladine, hamatine, ancistrobrevine A). This paper describes the isolation and structure elucidation of ancistrobrevine B (4), based on a novel 5,8'-coupling type.