Mies van der Rohe, perhaps,......?  

Are you serious? I'd hate to...
Are you serious? I'd hate to think you where.
;o)

What can it be?
I should embellish a bit. My first thought was that it might have been a van der Rohe. I'll explain. I worked at the east building at McCormick Place in Chicago. The first couple years that I worked there we would occasionally move furniture around to different rooms. On one occasion we threw out about ten pieces of furniture out. I realized later that a few of them were Florence Knoll sofas, they were so distinct looking. They probably made the rounds in the building and we were the last people to sit on them. They were trashed, but if fixed them up they would be fine. I asked a couple guys to put them in one of the storerooms, I just had an instinct about them. But, a couple days later I was told to grab an end an toss it in the dumpster.
Anyway, I seen this chair and I have hunch about it. Mies van der Rohe left a lot of stuff in that building , and after I realized what we threw out that day I was always digging around, looking for something.
Any ideas where this chair came from?

I don't know, but it's twin...
I don't know, but it's twin is on craigslist:
I don't think so...
http://austin.craigslist.org/fuo/1047875988.html

I am not in a position
to give you a clear answer, but a look at this chair coming from Mies van der Rohe's Weisenhof Siedlung project, one can not avoid seing many similarities.
Good luck in your search