Chords in C Dorian

C Dorian is built from the notes C, D, Eb, F, G, A and Bb. Its scale carries 2 flats. Harmonising that scale in thirds gives seven chords — 3 majors, 3 minors and 1 diminished — starting on Cm as the i. The chord on the fifth degree is Gm rather than a major V, so C Dorian has no leading tone and resolves by step and colour instead of by dominant pull — the sound that separates it from a plain C major.

Beyond those seven, C Dorian commonly borrows C (I), Em (iii), F (IV), G (V) and Am (vi) from the parallel major — the mixture chords that give a progression somewhere unexpected to go.