I am interested to know where the Eb diminished 7 in the first 4 bars of jazz standard I Wanna Be Around come from? My guess was that it relates as being a sort of tritone substitution for the V of the D-7, which is A7. Does this make sense?

My next question is how would you approach it when playing over the intro changes? We are nicely in C and then the Ebdim7 pops up. I have been playing a Diminished arpeggio but it feel s but boring!

I was also considering that Ebdim7 is the same diminished system as F7b9 which could be viewed as a Csus13b5#9 which TBH doesn't make much sense as a usable chord but maybe it could be used to played a mixolydian or altered scale? Another option is that B7b9 is also part of Eb diminished scale and of course can be seen as the VII of C major.

Perhaps I am over thinking this! Any thought? Thanks in advance!

  • Ebdim has another name - C dim...
    – Tim
    Feb 2, 2019 at 19:31
  • Good point, so basically it is just changing from C maj to Cm? Would that alter your approach to the Dm7 chord that comes after then?
    – Babaluma
    Feb 2, 2019 at 19:37
  • Not Cm. Co. So many semitone moves to get to Dm. Can't not work.
    – Tim
    Feb 2, 2019 at 20:30

3 Answers 3


The first few bars are sometimes chorded as:

Cmaj7, C6, Cmaj7, Cdim, Dm7...

sometimes as:

Cmaj7, C6, Em7, Ebdim, Dm7...

Either way, we usually see an Eb bass note for at least the second half of the fourth chord.

I'm not sure we can explain it as a substitution for A7, dominant of D, as the tritone C# - G is not present. Maybe we have to accept 'passing dim7 chord' as its own category.

What I'd play over it is the original melody, unless I was very sure I had something better!

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  • 1
    Agree! Passing dim is correct. Feb 2, 2019 at 23:25
  • I've had a similar issue with (Em7-Eo-Am7-D7). There's no way that diminished chord is a substitute for E7!
    – user45266
    Feb 4, 2019 at 23:32
  • Em7-Eo-Am7-D7 works best when the Eo is rooted on Bb.
    – Laurence
    Feb 4, 2019 at 23:42

The Ebo7 / Co7 chord

Note 1: Co7 can be used as a prolongation of C.1
Note 2: These enharmonically equivalent chords are also equivalent to F#o7

My interpretation is that the diminished chord has a dual function. It serves both as a prolongation of the Cmaj7, and it also functions as viio7/V; that is, F#o7 moving, eventually, to G(7).

So the overall analysis would be:

Imaj7 -- Io7 [= viio7/V] -- ii7 -- V7

What to play over it

Isolating the diminished chord, you can use a diminished (a.k.a. octatonic) scale. It's an eight-note scale proceeding by alternating whole and half steps (or half and whole steps) from the root. So:

C Db Eb Fb Gb G  A Bb C
C D  Eb F  Gb Ab A B  C

But you can also alternate between B locrian and the fifth mode of E harmonic minor.

Cmaj7: B C D  E F  G A B (B locrian)
Cdim7: B C D# E F# G A B (E h.m. mode 5)
Dmin7: B C D  E F  G A B (B locrian)
G7:    B C D  E F  G A B (B locrian)

1 See Steven G. Laitz, "The Complete Musician", 2nd ed. (2008, Oxford University Press), pp. 820 - 821 ("The Common-Tone Diminished Seventh Chord").


The main progressions in jazz are I ii V I jazz cadence and the I vi ii V7 progression.

There are 3 variations of the 1625 pattern where the iv is substituted: I (V7) ii V7 the 2 diminished chords I#dim7 and iiidim7:

In C major:

C am dm G7 will become:

C A7 dm G7

C C#dim7 dm G7

C Ebdim7 dm G7

So Eb dim7 may be considered as a substitution (variation) of am, but it is not exactly the tritonus substitution as this would be eb,g,a,db for a,c#,eb,g

Eb dim7 is actually a chromatic VIIdim7 to dm.

Source: Lesson 2, Swiss Jazz School (Berkley Jazz College)


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