Begun primarily as a recording project, the touring ensemble consisted of vocalist [a=Zac Pennington], [a=Rachael Jensen], [a=Eddy Crichton] and [a=Matt Carlson], all sharing a variety of instrumental duties. Former touring members [a=Jherek Bischoff] and [a=Sam Mickens] (of the band [a=Dead Science]) joined them for recording sessions.

Their music was notable for its combination of saccharine pop and experimental elements and has been compared with such disparate acts as Brian Eno, Philip Glass, Xiu Xiu and Phil Spector.

Originally taking their name from the Brian Eno composition "Swastika Girls", original members Zac Pennington and Jeremy Cooper self-released their limited run debut EP Christmas With Swastika Girls in 2002. After Cooper left the band, they changed their name and Pennington released (((GRRRLS))), the band's vinyl-only debut album on his own [l=Slender Means Society] label in 2004. This got recorded with the help of [a=Jherek Bischoff] and [a=Jamie Stewart (2)] (of Xiu Xiu fame). A split 7-inch with the band [a=Dead Science] was released by [l=Obsolete Vernacular] in 2007. In 2008 they switched labels to Germany's Indietronic source [l=Tomlab].

In 2017, bandleader Zac Pennington declared that the project had ended. Announcing, "Parenthetical Girls is over."