The District of Columbia Joint Landmarks Committee has given final approval to a proposed 74-foot-high Connecticut Avenue office building, which some of its Dupont Circle neighbors say would be too tall.

The height is a compromise - shorter than the 90-foot condominium apartment house that developer Jeffrey N. Cohen originally wanted on the property, but taller than the 60-foot height that citizen groups said would be in keeping with the scale of the neighborhood.

The property, now a parking lot, is at the corner of Connecticut Avenue and Hillyer Place NW, just north of Dupont Circle and next to a Beaux Arts structure that used to house Ellen's Irish Pub, also long-known as the Ben Bow bar.

Yesterday neither Cohen nor the objecting neighbors seemed happy with the compromise. But Cohen said he planned to start construction this fall.

"I spent more than $50,000 to design a condominium apartment building." Cohen said, "That's what I really wanted to put up. But when the (landmarks) committee said it couldn't be 90-feet, that made it uneconmical to do, and we had to switch to an office buildings."

John Wiebenson, an architect whose office is a block away, said that even at 74 feet the new building will be "fantastically out of scale for Connecticut Avenue and also for Hillyer Place, which is a charming and rather untouched little street.

"There will be a considerable amount of visual harm," remarked Wiebenson, who last month presented diagrams showing the hour-by-hour shadows that a 90-foot building would cast.

Under D.C. zoning laws, a 90-foot structure, either residential or commercial, is permitted on the site. But because the site falls within the Dupont Circle historic district, building plans must be approved by the landmarks committee, which includes members of the National Capital Planning Commission and the D.C. Fine Arts Commission.

Cohen said the new building will have a traditional Victorian facade with stone facing for the first two floors and brick walls and arched windows above. He said he bought the corner lot along with the Ben Bow bar for $1.12 million last February from the American Psychiatric Association, which had planned to tear down the bar and build a large office building, but encountered stiff opposition from bar patrons.

Cohen said he plans to use the Ben Bow building for his own office. He closed the bar in April.