Bioactivity-directed isolation of the extract of the cyanophyte Tolypothrix tjipanasensis has led to the isolation of fifteen new N-glycosides of indolo[2,3-a]carbazoles designated tjipanazoles A1, A2, B, C1, C2, C3, C4, D, E, F1, F2, G1, G2, I and J. The structures of the alkaloids were determined by physical methods, chemical degradation and synthesis. Tjipanazole J is the only compound having the pyrrolo[3,4-c] ring of previously described indolo[2,3-a]carbazoles. © 1991.