After four previous attempts by different developers to build on prime land lying vacant for 10 years in the main crossroads of Falls Church, the city's wait is over.

Last month city leaders gathered on the lot, at the southwest corner of Broad and Washington streets, to break ground for George Mason Square, a $10 million retail and office complex of three buildings that some see as the catalyst for revitalizing the downtown shopping area.

Fairfax City developer Berl Erlich, with the help of local residents, came up with a design that pleased Falls Church city administrators, The Falls Church Village Preservation and Improvement Society and his group, Office Space Management Inc.

It's not that city leaders in the past were totally opposed to other plans. They were willing to compromise with First Virginia Bank's plans for a 10-story headquarters that would stand three stories higher than the city's tallest building. But the bank decided to take its tower to Seven Corners.

Nor did the city reject out of hand a design for Mekong Center, a shopping complex proposed by a group of Vietnamese business persons from Arlington. Falls Church Mayor Carol DeLong concedes that one sketch having a distinct oriental flair "was not greeted with the wildest enthusiasm."

One thing seems certain in this two-square-mile town of 9,500 people: If you are building across the street from a Colonial Georgian-style red brick church completed in 1769 that is the Falls Church, it is better to dispense with the imposing and the incongruous.

"The church is the symbol of the community," emphasized the city's economic development coordinator, Elizabeth Baker. The Episcopal church, which once counted George Washington among its vestrymen, still has an active congregation, she noted.

And many, including Baker, DeLong and Erlich, believe that George Mason Square will be the keystone for further development in Falls Church's business district.

"I think it will change the impression of Falls Church. That corner has been vacant for so long that . . . to see something there . . . will make a major change in the visual impact -- people will say this is the downtown," Baker said. She said that city officials hope that the appearance of the complex will cause owners of nearby properties to reevaluate and upgrade the use of their land.

This year alone, three projects have been finished, including Gateway Plaza and the Jennings Office Park. And work on three other complexes started: the Broaddale Village Center, Independence Square II and the Georgetown-Kaiser Medical Facility, which is expected to be completed next fall.

"Falls Church in the past two years has experienced a little boom, as much as a small town can," noted Baker.

Baker credits the city's location, enhanced by the completion of I-66. "This is a good midpoint between downtown D.C. and the suburban markets," she said.

Developer Erlich, whose company has constructed, sold and rented 21 office buildings in Fairfax County during the past seven years, will finance the project with Tabari Investment Co., a firm based in the Netherlands.

Flexibility, Erlich claimed, was the key to his success with Falls Church's civic leaders. Zoning laws prohibit buildings that would clash with the city's village-like atmosphere and Victorian homes.

"We conferred with members of the Village Preservation Society. We met with them and they said, 'We want that and we want that.' It fit in with my plans, too. As a result we got approval in record time," Erlich said.

Sue Beachtel, president of the Village Preservation and Improvement Society, a watchdog group that advocates controlled growth, said the design of George Mason Square is an example of what can happen when builders and residents cooperate.

Falls Church architects Gauthier, Alvarado and Associates designed George Mason Square to mirror certain characteristics of the historic Falls Church, from the red bricks and its wall pattern to the size and shape of the windows. The two buildings of the complex to face Broad and Washington streets will be two stories in front but five stories in the back to give the appearance of a low-rise building to pedestrians.

An arcade similar to the one connecting Falls Church's sanctuary to the church's administrative offices will run along the Broad Street building. An arch between the two buildings will open onto a hexagonal public plaza with a fountain, traditional and abstract sculpture and park benches. The third building of six stories will be at the back of the plaza.

Each building will have about 30,000 square feet of space. Occupants for the first floors of the two front buildings could include a restaurant, a bookstore, a boutique, a hair stylist or a computer store.

"One of the items in the courtyard will almost surely be a bust of George Mason," said architect Ed Alvarado.

The project is expected to be finished in spring 1986.