 The relationship of "Synemporion" relative to other vesper bat genera is inconclusive.Researchers have been unable to extract its DNA from fossils, which is the only reliable way to examine phylogenetic relationships in this family of bats.It is unclear if "Synemporion" colonized the Hawaiian Islands from the Old World or the New World; most likely it belonged to one of the tribes of subfamily Vespertilioninae which make up the bulk of vesper bats but this is simply assumed because the minor subfamilies of vesper bats as well as the Vespertilioninae tribes were all well distinct from each other already by the time "Synemporion" became a separate lineage.