The new metabolite [1-(2‘-methylpropoxy)-2-hydroxy-2-methylpropoxy]butane was isolated from the cell-free culture supernatant of the marine bacterium Vibrio angustum S14 as part of studies investigatingthe role of chemical signals in prokaryote−prokaryote and prokaryote−eukaryote interactions. Thestructure was elucidated by interpretation of its high-field NMR and mass spectrometric data. [1-(2‘-Methylpropoxy)-2-hydroxy-2-methylpropoxy]butane induced the acylated homoserine lactone (AHL)reporter system in Agrobacterium tumefaciens and bioluminescence in Vibrio harveyi.