By denying Bangladesh permission to convert an Embassy Row mansion into a chancery, the D.C Board of Zoning Adjustment has served notice that it will seriously exercise its new powers to control diplomatic offices in residential neighborhoods.

Rejection of the Asian nation's application to occupy a three-story structure at 2501 Massachusetts Ave. NW climaxed months of controversy, pitting well-known residents against the State Department.

The zoning body's vote last week was unanimous, but its formal written opinion has not yet been filed. Henry Berliner Jr., attorney for the Bangladesh embassy, said he would wait for the opinion and consult with his clients before deciding whether to appeal to the courts.

Bangladesh is one of a few nations seeking to use old homes is the Embassy Row area. Several of the homes northwest of Dupont Circle are already being used as chanceries (embassy offices).

The Bangladesh application was fought by area residents through an organization called the Sheridan-Kalorama Neighborhood Council. One lawyer at a hearing last fall, representing an area resident opposing the application, was Thomas (Tommy the Cork) Corcoran, one of President Franklin D. Roosevelt's "brain trusters."

The opponents claimed, among othe things, that additional chanceries would over-saturate the area with traffic and parked cars.

In the wake of the hearing, the City Council considered legislation that would have barred new chanceries in residentially zoned neighborhoods. Opposed by the State Department, which feared retaliation against U.S. installations in foreign capitals, the legislation never was passed.

However, the D.C. Zoning Commission did adopt new rules permitting the BZA to review and, based on its findings, the prohibit chanceries.

George Blow, attorney for the Sheridan-Kalorama group, said the board decided the parking and automobile access required by the Bangladesh application would be too disruptive to the neighborhood. Members said the lot on which the old mansion stands is too small to park the 12 cars proposed in the embassy application.