Ionian #5 Mode on Guitar: Notes, Chords & Examples

The Ionian ♯5 mode is a bright, major-sounding mode with an unexpected twist: a raised 5th.

At first, it feels close to the regular major scale. You still get the happy major 3rd, the open major 6th, and the smooth major 7th. But the ♯5 adds a floating, surreal, almost “bent reality” quality.

For guitarists, Ionian ♯5 sounds:

Bright but unstable
Dreamy and cinematic
Major, but not ordinary
Slightly mysterious or futuristic
Great for progressive rock, fusion, film-score moods, and advanced songwriting

It is also known as Ionian augmented because the tonic chord is an augmented major chord.

Ionian ♯5 is the 3rd mode of harmonic minor

How does it sound?

Before anything else, let’s hear how it sounds. This can best be done by playing a chord from the mode, and playing the notes of the mode arpeggiated on top of it. This is the best and quickest way to determine the feel of a mode.

This can be quickly done using SLModes, a software dedicated to the music modes, and the following sound was generated by it:

Formula

The interval formula for Ionian ♯5 is:

1 2 3 4 ♯5 6 7

Compared to the regular Ionian mode, or major scale:

1 2 3 4 5 6 7

Ionian ♯5 changes only one note:

5 becomes ♯5

That one change makes a huge difference.

In C major, the 5th is G.

In C Ionian ♯5, the 5th becomes G#.

Notes in C

The notes of C Ionian ♯5 are:

C D E F G# A B

Interval breakdown:

C = 1
D = 2
E = 3
F = 4
G# = ♯5
A = 6
B = 7

This gives you a major scale sound with an augmented color in the middle.

The Chord That Defines the Mode

The defining chord of Ionian ♯5 is:

Cmaj7♯5

Notes:

C E G# B

Formula:

1 3 ♯5 7

This chord captures the mode better than any other chord because it contains the two most important ingredients:

The major 3rd: E
The raised 5th: G#
The major 7th: B

Together, these notes create a sound that is major, elegant, and unstable.

A simple C augmented triad also works:

C E G#

But Cmaj7♯5 gives you the full modal identity. The major 7th makes the chord feel more sophisticated and less like a simple augmented passing chord.

On guitar, try this voicing:

Cmaj7♯5

e|--0--
B|--0--
G|--1--
D|--2--
A|--3--
E|-----

Notes:

A string 3rd fret = C
D string 2nd fret = E
G string 1st fret = G#
B string open = B
High E open = E

It has a strange, open, beautiful sound.

Chord Progression (Example)

Because Ionian ♯5 is not as common as major, minor, Dorian, or Mixolydian, the safest way to keep the mode clear is to emphasize the Imaj7♯5 chord.

In C Ionian ♯5, the main chords are:

Imaj7♯5 = Cmaj7♯5
ii7 = Dm7
III7 = E7
IVmaj7#11 = Fmaj7#11
#v°7 = G#dim7
vi m(maj7) = Am(maj7)
viiø7 = Bm7b5

Roman numerals:

Imaj7♯5 – IVmaj7#11 – Imaj7♯5

Chords in C:

Cmaj7♯5 – Fmaj7#11 – Cmaj7♯5

This progression sounds wide, floating, and cinematic.

The Cmaj7♯5 gives you the core Ionian ♯5 sound, while Fmaj7#11 adds a progressive, dreamy color.

Try playing it slowly with clean guitar, chorus, delay, or shimmer reverb.

Guitar Fretboard Shape

Here’s the mode mapped across the full fretboard, generated with my software SLModes.

The diagram shows every occurrence of the mode across the neck:

🟢 Green dots = the root note, your anchor points
🟠 Orange dots = the rest of the scale tones

Why Guitarists Love This Mode

Ionian ♯5 is not an everyday mode, and that is exactly why it is useful.

The mode sounds major, but not simple.

It can feel:

Bright
Strange
Floating
Elegant
Futuristic
Slightly tense

The raised 5th makes the whole scale feel like it is lifting upward.

This is great when regular major sounds too predictable, but you do not want to go fully minor or dark.

Genres Where It Works Well

Ionian ♯5 fits especially well in:

Progressive rock
Progressive metal
Jazz fusion
Instrumental guitar music
Cinematic songwriting
Ambient guitar
Game and soundtrack-inspired music
Modern metal clean sections

It is not usually a “blues-rock jam” mode.

It shines when the harmony is more colorful and the arrangement gives the mode space.

Tips for Practicing

To practice a mode effectively, you only need two things:

An instrument to play the mode (your guitar is ready to go!)
A backing track that provides a harmonic context

The fretboard diagram above already show you where the notes are. The remaining piece is choosing an appropriate backing track to improvise over.

Practice with a drone

The simplest option is a single C drone.

You can create one using:

A looper pedal
A synth drone
A sustained bass note in your DAW
An open C tuning
Or any other source of a continuous C note

Because the accompaniment consists of only a single note, you are responsible for highlighting the intervals that define the mode. The more intentionally you emphasize its characteristic tones, the more clearly the modal sound will emerge.

Create modal vamps with SLModes

While a drone is an excellent way to hear a mode in isolation, a modal vamp often provides a more musical and rewarding practice experience.

A well-designed backing track naturally emphasizes the mode’s characteristic intervals, allowing you to focus on phrasing, melody, and expression instead of constantly trying to establish the modal sound yourself. As a result, improvising in the character of the mode often feels more intuitive.

There are many ways to build modal backing tracks, but SLModes can generate them for you in just a few clicks. For example:

Arpeggiated backing tracks — a repeating pattern that outlines every note of the mode.
Chord vamps — progressions built from chords that best reinforce the mode’s unique character.

This video shows you an example: