C# Tritone Substitution
ii – bII7 – I progression in C# major
C# Tritone Substitution — ii – bII7 – I
The C# ii–bII7–I tritone substitution (D#m – D – C#) replaces the dominant V with a chord a tritone away, creating a chromatic, mysterious color. With seventh voicings (D#m7 – D7 – C#Maj7), it delivers one of the most sophisticated sounds in jazz harmony.