Osborne has scooped a £31m contract to redevelop Hobhouse Court in Trafalgar Square.
The firm will deliver the construction contract under a £75m regeneration of six properties on the Hobhouse Estate for developer Alaska Developments.
A total of 20 apartments, 1,100 sq m of office space and 650 sq m of retail units will be delivered.
Existing underground vaults will be turned into new art gallery space to be used by the Royal Watercolour Society.
Work on site is expected to start imminently and complete by June 2019.
The Hobhouse Estate deal follows on from Osborne’s £22m revamp of Mercers’ Yard in nearby Covent Garden.
The contractor also revealed to Construction News in April that it is looking to position itself as more of a housing services provider than a contractor.
Osborne Communities managing director Nick Sterling said the firm is aiming to “de-risk” its business by looking to the housing services market.
While the group will remain in construction, it wants to “seek markets that give a better margin than construction”.