Chromatic mediants are an interesting harmonic concept often used in guitar music to add color and emotional depth. Simply put, a chromatic mediant is a chord that is a third away from the original chord but differs by at least one accidental (note outside the key), making it "chromatic" rather than strictly diatonic.

For example, if you're in the key of C major, the diatonic mediants are E minor (iii) and A minor (vi). A chromatic mediant might be E major or A major, both of which are a third from C but contain notes not found in the C major scale. These chords create unexpected shifts that can sound fresh or dramatic.

In guitar music, chromatic mediants are often used to add sophistication or surprise. Players might move between a tonic chord and its chromatic mediant to evoke a dreamy or cinematic feel. Because guitar chords can be easily voiced and shifted, guitarists can experiment with chromatic mediants by sliding shapes or changing a single note to create complex harmonies without complicated fingerings.

To try it yourself, start by playing a basic chord like C major, then switch to an E major or A major chord and listen to how the mood changes. This jump of a third with altered notes introduces tension and interest, enriching your chord progressions.

In summary, chromatic mediants in guitar music offer a simple yet powerful tool for expanding harmonic vocabulary beyond standard key boundaries, making compositions or improvisations more colorful and engaging.