Bmaj7, Cdim7, C#m7, F#7

Analysis

Heard in B major

Progressions in these changes

• All the chords

  Diminished Passing Turnaround in B

  The I-VI-ii-V with a diminished 7th chord on #I in place of VI7, so the bass rises by half steps from I to ii.

Scales to play

• Over Bmaj7 · Imaj7

  B Ionian

  The major scale and its modes are the most commonly used scales in western music.

• Over Cdim7 · ♭ii°7

  C Altered Diminished

  Mode 7 of Harmonic Minor

• Over C#m7 · ii7

  C# Dorian

  Mode 2 of Major

• Over F#7 · V7

  F# Mixolydian

  Mode 5 of Major