Billy Strayhorn was arranger and occasional second pianist and lyricist with Duke Ellington beginning in 1939--the collaboration continued until the 1960s. Among his hundreds of compositions best known are "Lush Life" and "Take the A Train". During the pre-bop period of the mid 1940's Strayhorn experimented with false modulations and expanded the swing vocabulary of chord voicings.
In 1993, Billy Taylor recorded and produced "Dr. T" featuring Gerry Mulligan on GRP records (GRD-9692). Here's an exerpt from Lush Life, a Billy Strayhorn composition.