- Imago (2009)flute, clarinet, piano, percussion, violin, viola, cello and fixed medium
- Immobilis in mobili (1977)flute, oboe, clarinet, violin, viola, cello, 2 pianos and vibraphone
- Impasto (2006-08), 45:46fixed medium
- Impasto 46 (2006), 16:29
- Impasto 128 (2008), 19:31
- Impasto finale (2008), 9:38
- organ (pedalboard solo)
- Impromptu 2 (1995), 16:00piano, synthetizer (Roland JV-80, Max/MSP sampler) and stereo fixed medium
- Improvisation 19 (2017), 5:00beamophone and fixed mediumCycle: Résonance Kandinsky
- Improvisation 26 — Ramer (2003), 5:00cello, percussion and processingCycle: Résonance Kandinsky
- Improvisation à la gorge (2008), 5:00hyper-fluteCycle: Résonance Kandinsky
- Improvisation sur E.B. (1971)organ
- Improvisation sur Mallarmé I (1958, 62)solo soprano, harp, vibraphone, bells and 4 percussions
- solo soprano, harp, piano, celesta, bells, vibraphone and 4 percussions
- Improvisation sur Mallarmé III (1959, 84)solo soprano, 4 flutes (alto and piccolo), tenor trombone, mandolin, guitar, 3 harps, celesta, 7 percussions, 5 cellos and 3 double basses
- organ
- Improvisations III (1969)clarinet and piano
- In & Out 1 (2004), 10:00violin, cello, processing and video
- In a low voice (1991, 94)soprano, clarinet (bass clarinet), keyboard, piano, cello and fixed medium [pre-recorded children’s chorus]
- In auditorium (1998), 16:002 flutes, piccolo, 3 oboes (including English horn), 4 clarinets [
B -flat,E -flat, bass and double bass], 2 bassoons, 4 horns, 4 trumpets, bass trombone, 2 trombones, tuba, harp, piano and 4 percussions - In Between (2008), 17:00string quartet and gamelan
- In
C (1964)small ensemble, chorus and solo voice - In der andern Welt... (1990)soprano, violin, cello, piano
- In Etwartung (1994)saxophone quartet and 6 percussions
- In girum (2013)wind quintet
- In My Twenties (2020-21), 11:00flute, clarinet, violin, cello, piano and vibraphone (tom)
- In Nomine (2000)viola
- In Paradisum (2008), 6:00soprano and organs
- In Spite of Myself, 1:00pianoCycle: One Minute More
- In Te Domine speravi (1965)organ
- In the Asylum (2000), 13:00violin, cello and piano
- In the Flesh (2003), 11:00orchestra
- In the High Branches (2008)string quartet and gamelan
