According to Cinema Treasures:
"The Pantheon opened its doors in 1918 for the Lubliner & Trinz chain, located in the Uptown neighborhood on Sheridan Road at Eastwood Avenue. At the time it opened, it was said to have 3000 seats. It was the largest movie theater in the area until seven years later, when the nearby Uptown Theatre opened. The theater cost over $750,000 to build, and was decorated in the style of the Italian Renaissance, complete with a double organ and a 30-piece orchestra. Within a few years, the operation of the Pantheon was taken over by Essaness until, like so many other theaters in Chicago, it was added to the always-expanding Balaban and Katz chain. By the 50s, the Uptown neighborhood was no longer the entertainment mecca it was from the 1910s through WWII, and the Pantheon's fortunes rapidly declined, as did the rest of Uptown. The Pantheon remained in operation into the early 60s. It was demolished in 1962 and was replaced by a parking lot."
If Ahlschlager's name sounds familiar, it's because he designed a number of Uptown's most prominent buildings, including the Sheridan Plaza Hotel. Get a PDF download of some of his work here: Walter Ahlschlager.