Mace will project manage the seven-storey office scheme at 7-10 Hanover Square, where work will start in August after demolition is complete.
The 58,000 sq ft Portland stone-clad building will be built opposite the planned Bond Street Crossrail station and include ground floor retail space.
To the rear of the property on Princes Street a separate residential building is planned with five luxury two-bedroom apartments and a three-bed duplex penthouse.
At 103-109 Wardour Street in Soho, Mace will oversee another office and resi scheme, designed this time by Sheppard Robson.
The project will provide 15 luxury flats and involve the alteration of the existing core, a replacement of the rear façade, and conversion and extension of seventh floor office accommodation into high spec residential.
Cara Bamford, Partner at Make Architects, added: “This mixed use scheme will be a fabulous, modern addition to the classical architecture in Hanover Square.
Rather than being a pastiche of the existing traditional architecture, our contemporary buildings will enhance the surroundings, providing high quality commercial space alongside much needed residential accommodation and ground floor retail and restaurant units which will breathe life into the Square.”