A phytochemical investigation on the branches and leaves of Illicium burmanicumled to the isolation of two unique allo-thujane-phenylpropane and lavandulane-phenylpropane hetero-adducts (1 and 2), two new prenylated phenylpropanoids (3 and 4), and one new neolignan (5). Their structures were established by comprehensive NMR and CD spectroscopic analysis. Burmaniols A (1) and B (2) showed appreciable cytotoxicity against A549 and HCT116 cells with IC50 values of 6.40-7.76 mu M.