(chemistry) A bis(indolyl)imidazolealkaloid containing bromine derived from sponges, spongotine-B: (6-bromo-1H-indol-3-yl)-[5-(1H-indol-3-yl)-4,5-dihydro-1H-imidazol-2-yl]methanone (spongotine A has bromine in another position and spongotine C has two bromine atoms.