The property doesn’t look like much — a weed-strewn eyesore at the northwest corner of 21st and Prairie in the shadow of McCormick Place.

But the vacant piece of land proved to be very profitable for Drapac Group LLC, Australian developers who hired Langdon D. Neal, one of the city’s most politically connected lawyers.

Neal was a registered lobbyist for Drapac when it paid $1,020,000 for the 21,857-square-foot property in the shadow of McCormick Place in May 2013 — its first deal in Chicago.

Little more than a year later, Neal’s firm helped another client, the Metropolitan Pier and Exposition Authority — the government convention agency known as McPier — buy the Drapac property to turn into a dog park and playground. The aim was to placate neighbors upset with Mayor Rahm Emanuel’s plans to build a basketball arena for DePaul University and a Marriott Hotel near their homes just west of McCormick Place.

McPier paid Drapac $5,473,750 — meaning Neal’s current client helped his former client make a 400 percent profit in just 14 months, records examined by the Chicago Sun-Times show.

The authority — which will own the hotel and arena — had no appraisal to determine the value of the Drapac property it bought from Neal’s former client last summer.

Neal informed McPier about his earlier work for Drapac, according to a spokeswoman for the agency who says Neal received a waiver from McPier to be involved in the deal that profited his former client.