My Songs Know What You Did in the Dark (Light Em Up)
Commercially, "My Songs Know What You Did in the Dark (Light 'Em Up)" debuted on charts worldwide with modest success, debuting in the top five in the United Kingdom and at No. 36 on the Australian ARIA Chart, charts the band have previously received success from with singles like "This Ain't a Scene, It's an Arms Race" and "Thnks fr th Mmrs". On the Billboard Hot 100, the song debuted at No. 26 and No. 8 on US Rock Songs; it reached No. 2 on iTunes upon its release. Fall Out Boy performed the song on Jimmy Kimmel Live! for their first post-hiatus TV performance on February 13.