Key
Chords in Bb Lydian
Bb Lydian is built from the notes Bb, C, D, E, F, G and A. Its scale carries 1 flat. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Bb as the I. The chord on the fifth degree is F, a major V, so Bb Lydian has the leading tone that makes a F-to-Bb cadence sound final.
Beyond those seven, Bb Lydian commonly borrows Bbm (i), Cdim (iiø), Db (bIII), Ebm (iv) and Fm (v) from the parallel minor — the mixture chords that give a progression somewhere unexpected to go.
The seven chords
Extended to four notes each, the same seven degrees give Bbmaj7, C7, Dm7, Em7b5, Fmaj7, Gm7, Am7.
Borrowed chords
Capo 5 and play F Lydian shapes to sound Bb Lydian.
All eight capo positions for Bb Lydian →