D# Tritone Substitution
ii – bII7 – I progression in D# major
D# Tritone Substitution — ii – bII7 – I
The D# ii–bII7–I tritone substitution (Fm – E – D#) replaces the dominant V with a chord a tritone away, creating a chromatic, mysterious color. With seventh voicings (Fm7 – E7 – D#Maj7), it delivers one of the most sophisticated sounds in jazz harmony.