The deal, effective from 1 January, sees Green-I's Ian Woodall and Andrew Frengley form a new executive board and installs former Canegreen operations director Richard Martin as managing director. Both firms were set up in 1982 as associate business units to rental production company Canegreen.
Woodall said: "We could see an obvious synergy in rolling Canegreen Commercial into Green-I since both companies had reached the top in their respective fields.
"The move was triggered by the large number of rental staging events we were being asked to produce in venues for which we had previously carried out installations."
As well as being a design, sales, installation and maintenance company, Green-I will look to increase its hire activity via the extensive audio stock Canegreen Commercial has used to service corporate events at venues such as the Grosvenor House Hotel, Natural History Museum and Royal Albert Hall.
Managing director Martin has been with the company since 1996. He said: "By bringing the two forces together via acquisition, we can now offer a complete range of services to both companies' respective client bases from a single resource."
Yan Stile, managing director of parent company Canegreen, said: "This acquisition makes perfect sense for everyone. While the original company continues to focus on the concert touring market, there is still a massive market to plumb in the corporate event and party sector as well as installation."