Key
Chords in B Lydian
B Lydian is built from the notes B, C#, D#, E#, F#, G# and A#. Its scale carries 6 sharps. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on B as the I. The chord on the fifth degree is F#, a major V, so B Lydian has the leading tone that makes a F#-to-B cadence sound final.
Beyond those seven, B Lydian commonly borrows Bm (i), C#dim (iiø), D (bIII), Em (iv) and F#m (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 Bmaj7, C#7, D#m7, E#m7b5, F#maj7, G#m7, A#m7.
Borrowed chords
Capo 6 and play E# Lydian shapes to sound B Lydian.
All eight capo positions for B Lydian →