Employers are being invited to look round the new £8.5m iCon Centre in Northamptonshire and consider taking office space.
The Daventry building was designed to boost the construction industry in the county and is hoping to attract tenants ahead of its opening in April.
In July, before completion, it won a national Green Apple Award for its environmentally-friendly design.
It uses renewable energy, taken from the air, via customised heat pumps.
The building off Eastern Way, run by charitable organisation iCon East Midlands, has 55 units for businesses specialising in sustainable construction, a conference hall and cafe.
Funding for iCon's construction was awarded by the East Midlands Development Agency, the European Regional Development Fund and West Northamptonshire Development Corporation.