Manchester-based Vision Developments has purchased Invicta House, located within Spinningfields in Atkinson Street, from Maple Grove Developments.
Maple Grove sold its freehold interest in the 10,000 sq ft building to the developer following competition between several other interested buyers.
Andy Lavin, director of Maple Grove, said: "We placed this property on the market at the beginning of September with the aim of generating a profit for the wider group and we are delighted with the outcome."
Agents Christopher Dee acted on behalf of Maple Grove and invited offers of about £3.5m for the building.
It is the first major purchase in Manchester by Vision Developments, a joint venture between Irish property developer Morgan Leahy and Stephen Cliff, the former director of Ask Developments.
Plans for Invicta House will be unveiled shortly.