Benzo[c]phenanthridine alkaloids sharing a tetracyclic structural motif, are an important class of nitrogencontaining small molecules and are used for the treatment of a number of diseases. This review presents a comprehensive survey of the occurrence, chemistry, biochemistry, and biological activity of benzophenanthridine alkaloids. Synthetic approaches to a number of benzo[c]phenanthridine are disclosed in this Minireview. Biosynthetic Relationship of Tetrahydroisoquinoline and Benzo[c]phenanthridine AlkaloidsA plausible biogenetic connection between tetrahydroisoquinoline and benzo[c]phenanthridine alkaloids is shown in Scheme 1. Protopine (3 a) can undergo a demethylation followed by reductive amination to generate tetrahydroisoquinoline alkaloid, stylopine (2 a). The latter can further undergo an [a] Dr. oxidative CÀ N bond cleavage leading to intermediate aldehyde 4 a, which can form a new CÀ C bond (see, 4 c) assisted by in-situ prepared enamine. An elimination followed by oxidation leads to the synthesis of norsanguinarine (1 a).