A complete study of the bisbenzylisoquinolines with an ether and a biphenyl bridge isolated from Guatteria guianensis enable us to establish rules to correlate spectral data and absolute configuration in this type of dimer. Six new dimers have been isolated, (+)-2'-norfuniferine 1, (+)-2'-nortiliageine 3, (+)-guattamine 5, (+)-2'-norguattaguianine 6, (+)-2,2'-bisnorguattaguianine 8, and (+)-guattaminone