Property group Goodman has secured a deal for its 55,000 sq ft, four-storey Eastside Locks office scheme.
The deal is part of the continued expansion of BCU's city centre campus which has seen it develop neighbouring buildings like Parkside.
Goodman commenced construction of the Cardigan Street office - initially called 1 Cardigan Street - on a speculative basis in November 2014, anticipating early interest given Birmingham's growing profile as an investment and business location and being adjacent to the planned HS2 Curzon Street station.
James Raven, development director of UK business parks at Goodman, said: "Our belief in the city's growth underpinned the decision to begin work on the Cardigan Street scheme as a speculative development last year.
"Birmingham is attracting record levels of inward investment, has more start ups than anywhere outside of the capital and tops the UK's quality of living rankings for regional cities.
"With HS2 also moving forward, demand for developments in the city is set to rise and we are investing now to ensure Eastside can offer the high quality accommodation needed by tomorrow's businesses.
"For Goodman, securing this lease with Birmingham City University during the early stages of construction will enable us to commit to the next phase of speculative office development and implement plans for the first amenity hub at Eastside Locks. We look forward to announcing more details in the near future."
The development of 6 Cardigan Street is the latest project in the first phase of Goodman's partnership with Birmingham City Council and the Homes and Communities Agency.
The partnership plans to build up to a total of 800,000 sq ft of office space at Eastside Locks together with shops, bars, restaurants, residential spaces and a hotel, all situated within a landscaped and managed environment alongside the Digbeth branch of the Birmingham and Fazeley Canal.
Eastside, the largest regeneration project in Birmingham, continues to build its position as the city's knowledge and innovation quarter.
Cliff Allan, vice-chancellor at BCU, said: "This is the next phase of our city centre campus expansion at Eastside, transforming a neglected part of central Birmingham into a thriving focal point for education.
"This development will allow us to bring more of our staff across from our Perry Barr site in support of all the work now taking place right in the middle of the UK's second city."
BCU opened the first phase of its city centre campus in Eastside in 2013, building on its existing presence in Millennium Point. It is currently developing a new conservatoire on the campus, which is scheduled to complete in 2017.
The head office of the university is also now located at the campus.
Eastside is home to other educational institutions including Birmingham Ormiston Academy and Aston University.
Leader of Birmingham City Council, Sir Albert Bore, said: "Eastside Locks represents a significant opportunity to further boost Birmingham's economy and that of the region as a whole, attracting inward investment from international businesses and driving the growth of local organisations.
"The site is ideally placed to host an innovative business hub."