In previous studies on the chemical constituents of Murraya euchrestifolia hayata(Rutaceae) collected in Taiwan, we preliminarily reported the first isolation and structure of a binary carbazole alkaloid, murrafoline-A (1). Since then, the isolation and spectroscopic structural elucidation of three new binary carbazoles, murrafoline-B (2), -C (5), and -D (3), have been reported. This paper describes in detail the structural elucidation of these novel binary carbazole alkaloids and also introduces two additional ones, murrafoline-G (4) and -H (6). Treatment of a mixture of girinimbine (7) and murrayafoline-A (8), which are monomeric carbazoles and structural components of murrafolines, with Nafion 117, an acidic perfluorinated ion-exchange resin, was found to produce murrafoline-D (3), -G (4), and -H (6). © 1993, The Pharmaceutical Society of Japan. All rights reserved.