Secondary dominants
Turn a diatonic chord into the dominant of the next chord to create a brief, directed tonicisation.
Interactive listening
Hear the harmony in time
Compare the examples at one tempo.
Diatonic turnaround
Am7 belongs to C major and moves gently to Dm7.
With a secondary dominant
C♯ in A7 becomes a leading tone to D, making Dm7 sound like a temporary tonic.
Watch it in context · Signals Music Studio
Secondary Dominants: Write Better Chord Progressions!
Hear how temporary dominant chords tonicise diatonic targets and add momentum without permanently changing key.
Open on YouTube (opens in a new tab)Borrowing a dominant function
A secondary dominant is the dominant of a diatonic chord other than the tonic. A7 is not diatonic to C major because it contains C♯, but it is V7 of D. Placing it before Dm7 briefly makes ii sound like a local tonic without establishing a full modulation.
The accidental is purposeful: C♯ leads upward to D, while G—the seventh of A7—falls to F in Dm7. Those semitone resolutions explain the stronger pull compared with Am7.
Label the destination
Write secondary dominants as V7/x, where x is the chord being tonicised. A7 before Dm7 in C is V7/ii; D7 before G7 is V7/V. The label describes function rather than the chord’s temporary scale.
Applied dominants can form chains. In Cmaj7–A7–D7–G7, each dominant points to the next chord until G7 finally resolves to C. Track the changing thirds to outline the progression when improvising.
- Find the destination chord.
- Build a dominant seventh a perfect fifth above its root.
- Resolve the new leading tone and chordal seventh by step.