Energy Plaza (The Sinclair)

The tower was put up for ARCO Oil and Gas on the site of the company's former headquarters, on Bryan Street in downtown Dallas: planning began in May 1978, construction in May 1980, and it was finished in August 1983. It first held Arco's regional offices, then other tenants, among them the electricity distributor Oncor and the Federal Deposit Insurance Corporation.

Credited to I. M. Pei & Partners, it had as lead designers Henry N. Cobb, Pei's partner, and Pershing Wong. It is one of Cobb's Dallas towers, alongside One Dallas Center (1979) and Fountain Place (1986).

Largely empty by then, the tower was bought in 2022 by Todd Interests, together with Moriah Real Estate and Zurich Alternative Asset Management. The Dallas firm HKS designed the conversion, the general contractor Brasfield & Gorrie carried out the work, and the building reopened in 2024 as The Sinclair.

The tower stands where two downtown street grids meet, on a trapezoid-shaped lot. It steps back above a triangular base, then rises as a crisp prism to 633 feet (about 193 m), faced in grey granite. A vertical notch cuts into it up to the 42nd level; at that point half of the building stops under a roof, while a triangular shaft carries on for seven more levels. Inside, the notch yields extra corner offices and meeting rooms; outside, it sharpens the tower's angular geometry. A frame tying the steel columns of the facade to the concrete core leaves the office floors free of columns.

By pulling the tower back from the sidewalk, the firm made room for a public plaza of 14,000 square feet (about 1,300 m²), which together with nearby Thanks-Giving Square opens up space amid the crowded downtown; below ground, the building joins the pedestrian tunnels that connect downtown Dallas buildings.

In the conversion, the entrance lobby kept its original 30-foot (about 9 m) height. On the street side, the stone walls of the lower levels gave way to clear glass panels, and balconies were opened at the corners of the triangular floors. The granite plaza was given planting, a fountain and a restaurant terrace.

Since the conversion, the middle of the building has stayed in office use (450,000 square feet, about 42,000 m²), while the upper floors hold 293 apartments; each use has its own entrance and lobby.

The tower stands at the corner of Bryan Street and Ervay Street in downtown Dallas. It is a private building, seen from the street.