Subdivide Commercial Lot

[Brandon E]

I've been going back and forth with this dilemma for over a year so it will be good to get some honest advice on the issue.

There is a vacant lot nearby in a residential area that I am interested in purchasing; however, the lot is attached to a large commercial property which is behind it. I have researched the tax records and found the owner's contact information.
Where should I go from this point? Should I go to the city zoning department and inquire about the subdivision or should I go to the owner and start negotiation? Would it be difficult to convince someone to sell off empty land they haven't ever used, or will the owner probably not want the zoning hassle........ Any thoughts?