Eighteen isoquinoline alkaloids have been isolated from the Indonesian annonaceous plant Popowia pisocarpa. Among them, bipowine (1) and bipowinone (2) represent a novel type of natural dimeric aporphinoid. 4-Hydroxywilsonirine (3), as well as isopycnarrhine (13), have not been previously reported. The structures of these new compounds have been established on the basis of their spectral data and chemical properties. Fourteen other known alkaloids were also isolated; most of them are apotphinoids. The alkaloidal content of P. pisocarpa is specially complex since, with the seventeen bisbenzylisoquinolines already described, thirtyfive alkaloids are now recorded for this species. Finally, dehydronorglaucine (19), prepared from norglaucine, has been dimerized into the new bis-7,7’-dehydronorglaucine (20). © 1986, American Chemical Society. All rights reserved.