Brandywine Realty Trust is seeking tenants for a planned second office building on its 23-acre Plymouth Meeting property that it dubbed the Metroplex.

The so-called Metroplex Two office building on the tract near the intersection of I-476 and the Pennsylvania Turnpike would comprise 280,000 square feet of office space, Philadelphia-based Brandywine said in a release.

Real estate services firm JLL has been retained to market the planned building, Brandywine said. Construction is set to begin once an anchor tenant is secured.

The new offices would join the existing 120,000-square-foot Metroplex One building at the site. That building’s tenants include mortgage lender New Penn Financial LLC and children’s clothing maker Fishman & Tobin Apparel LLC.