Mulligan/Griffin and Associates Inc. and the Reston Land Development Corporations have contracted to build a $50 million office complex on 35 acres in Reston.

The complex, which has been named Tech Park Reston, will be located on Sunrise Valley Drive and the Dulles access road, at the intersection of the proposed Springfield bypass. It will contain approximately 550,000 square feet of space for about 3,000 employes.

Mulligan/Griffin, a firm that specializes in the development of facilities for local high technology research and development companies, is currently developing about 890,000 square feet of office and "high tech" space in Maryland. Those projects are Tech Park 270 in Gaithersburg, an office park that will become the headquarters for NUS Corp., and an executive office building at 1700 Research Boulevard in Rockville.

The company recently completed Twelve Oaks Office Park in Rockville, which has been leased to IBM and General Electric Information Services Co.

Tech Park Reston is the first project in Virginia for Mulligan/Griffin.

Developments in real estate in the Washington area:

* Wheeler Industries, a national systems engineering firm primarily associated with the U.S. Navy, has leased 10,884 square feet of space in the Airport Plaza Office Building in Crystal City.

* Piedmont Airlines will lease 20,000 square feet of space in the Commerce Park II Building in Reston for the first local Piedmont Reservation Center. The center, which is scheduled to open on March 29, is expected to employ about 500 people by the time its operations are fully established.

* An older office building at 722 9th St. NW was sold recently for $6.4 million by New Victor Co. to Convention Associates.