Arcadia-based Hinshaw's dedicated their WHITTIER QUAD store in March 1953. One of two locations, it was shuttered in January 1992.
Photo from

Pasadena's F.C. Nash Company also operated a store in the original QUAD. There were other Nash's locations in Pasadena, Alhambra, Arcadia, Fullerton and the POMONA VALLEY CENTER mall, in Pomona. This general merchandise chain folded in the early-1970s.

A view of WHITTIER QUAD taken before its roofing renovation, which took place in 1974. This shows the northern mallway, with Bank of America on the left and Barker Brothers Furniture on the right.
Photo from "TokyoMagic!"

May Company California opened a WHITTIER QUAD store in 1965. 22 years later, the building incurred heavy damage from the Whittier Narrows Earthquake. Here we see what was left of the 3-level "May's Whittier" parking structure after the temblor hit.
Photo from NOAA (National Oceanic and Atmospheric Administration)