The Design Exchange has been located in the old Toronto Stock Exchange at 234 Bay Street, designated a heritage property in 1978, since 1994.
The signage says:
Its design was revered as an architectural and technological marvel, a ‘masterful expression of its time, place and function’ with ‘the most up-to-date trading floor in the world.’
In 1983, the Stock Exchange moved to its current headquarters at the corner of King and York.
In 1994, Kuwabara Payne McKenna Blumberg Architects (KMPB) incorporated the historic Trading Floor and TSE structure into the unique Toronto-Dominion Centre complex.

While the Design Exchange did have one current exhibition on (The Futurists: Young Canada Transforms Tomorrow), I was more interested in the historic building, for an odd personal reason. I could swear I was brought there on an unusual date long ago, but I wasn’t feeling any recognition of the space. It must have been a different building?
In any case, the art deco or moderne style features gladdened my heart. Look at this staircase!

The descriptive sign says:
Stainless steel with lacquered birch handrail swirls upward, inviting visitors to ascend from the first floor to the second floor.

I’ll be glad to return to have a better look at the Charles Comfort murals (opens 7-page PDF), to which my quick cell phone snaps did no justice whatsoever, and to see the third floor exhibition hall, when it reopens.
Design Exchange is museum no. 61 in my #100museums challenge (see 100 Museums Challenge).