Harmonizing Scales III: Minor Pentatonic

Now that we've harmonized major and the melodic minor scale, let's talk about some other scales, namely the one that every rock player is extremely familiar with: the minor pentatonic scale, I'll use A so I don't have to deal with any sharps or flats.

A C D E G

Now let's go through the same process as before building triad chords by skipping every other note (ie the 1 3 5 of a pentatonic scale).

A D G

This ends up being the root, fourth and minor seventh of the minor scale, which will function as an A7sus4(omit 5).

C E A

This will function as a C6, again without the fifth.

D G C

D7sus4 Another 7sus4 chord, without the fifth.

E A D

E7sus4 – once more without the fifth.

G C E

G6sus4 – without the fifth.

So we get

I – A7sus4
II – C6
III – D7sus4
IV – E7sus4
V – G6sus4

Move up in fourths changes because this is only a 5 note scale:

I IV II V III I

This progression will sound pretty cool, however it's fairly dissonant, you can use the notes within the scale to pull other extensions, forming different chords, for example, A C E G are all in there, meaning your i chord could also be an Amin7.

The chord substations also change:

I and III
II and IV
III and V would form your substitutions. Therefore, using this information:

Gsus4 Dsus4 Amin

Actually forms a pretty interesting progression, and it's pulled completely off the minor pentatonic, this can really expand your vocabulary of progressions, and substitutions.

Related:
New ways to use pentatonic scales