Chords in F# Lydian

F# Lydian is built from the notes F#, G#, A#, B#, C#, D# and E#. Its scale carries 7 sharps. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on F# as the I. The chord on the fifth degree is C#, a major V, so F# Lydian has the leading tone that makes a C#-to-F# cadence sound final.

Beyond those seven, F# Lydian commonly borrows F#m (i), G#dim (iiø), A (bIII), Bm (iv) and C#m (v) from the parallel minor — the mixture chords that give a progression somewhere unexpected to go.