As part of a study on the structure-activity relationship of antitumor-active tropolonederivatives, a series of bistropone analogues, related to potently active bistropolone 1a, were synthesized and tested for their antitumor activity in in vitro (KB cell) and in vivo (leukemia P388 in mice) systems. The methoxytropones 3 and 5, hydroxytropothione 10, and (N-methylamino)tropones 12 and 13 were inactive