Display screen or portion thereof with transitional computer graphical interface thereon

FIG. 1 is a front view of a display screen or portion thereof with transitional computer graphical interface thereon showing a first image in a sequence according to a first embodiment of the claimed design;

FIG. 2 is a front view of a second image in the sequence thereof;

FIG. 3 is a front view of a third image in the sequence thereof;

FIG. 4 is a front view of a fourth in the sequence thereof;

FIG. 5 is a front view of a display screen or portion thereof with transitional computer graphical interface thereon showing a first image in a sequence according to a second embodiment of the claimed design;

FIG. 6 is a front view of a second image in the sequence thereof;

FIG. 7 is a front view of a third image in the sequence thereof;

FIG. 8 is a front view of a fourth in the sequence thereof; and,

FIG. 9 is a front view of a fifth image in the sequence thereof.

The appearance of the transition is sequential from FIG. 1 to FIG. 4 in the first embodiment, and from FIG. 5 to FIG. 9 in the second embodiment. The process or period in which an image transitions to another image forms no part of the claimed design.

The longer-incremented broken-lines showing an electronic device and the broken lines showing a display screen boundary are portions of an article of manufacture that are excluded from being part of the claimed design. The closely spaced broken line showing of text, numbers and symbols illustrate portions of the transitional computer graphical interface and form no part of the claimed design.