Given the erratic history of South Street, something could always change. But it looks as if, by this time in 2014, both ends of the city's most irrepressible district will be capped by shiny new condo developments.

The currently vacant sites have been caught in limbo for a decade or more. Like forlorn urban wallflowers, they have wishfully accepted invitations from a succession of rich suitors - Will Smith among them - who ultimately decided the dance ticket wasn't worth the trouble or money.

Now, finally, it looks as if the right match has been made, said Brian Emmons, vice president of Toll Bros., the company developing both properties.

Last week, students from the University of Pennsylvania rode bicycles past the cyclone fences on the 2400 block of South Street where backhoes beeped, cranes moaned, and construction workers connecting sewer lines shouted up from 8-foot-deep holes in the ground.

On this cleared lot, which was once Graduate Hospital's parking garage, 68 townhouses and 59 condos will soon appear, Emmons said, along with a 2,400-square-foot retail space nearby. The homes, he said, will sell for between $490,000 and $800,000.

Head down South Street to where it dead-ends at Front and turn left and you will find the other property, looking less promising - broken concrete sprouting weeds, crumbling retaining walls covered in graffiti.

But with only one zoning approval remaining, Emmons said, this project, too, will soon be under way. Covering most of the city block between the eastern hem of Headhouse Square and Front Street, it will be transformed into 69 condominiums with a roof deck overlooking the Delaware River, and a 110-space underground parking garage, some of which will be sold to nonresidents.

"Originally," he said, "we proposed 73. But we presold five of them to one person who is combining them into one large penthouse." The price? "Close to $4 million."

If you'd like to understand one of the many problems that have stymied these long-awaited developments, Douglas Randall has a story for you.

In the 1970s, Randall owned a jewelry store in New Market, a retail complex on the Front Street site. Customers used to line up at his display cases. Outside his shop, the not-yet-famous Penn and Teller would perform, busking for change. Unicyclists would spin past the waterfall in the plaza. Upstairs at the Rusty Scupper, patrons would gather for drinks before dinner.

"South Street was cooking. The place was packed," Randall recalls.

But the neighbors who lived in the historic brick townhouses of Society Hill were miserable.

The market was noisy and crowded and there was never enough parking. Within the complex was a Dumpster and an industrial trash compactor.

"One night, the compactor broke. You could hear it grinding, grinding for hours."

About 10 p.m., Randall said, through the frosted glass at the back of his store, he saw sparks flying. He ran out to find a long-suffering neighbor hacking the compactor to pieces with a fire ax.

A fundamental paradox of urban development, said Emmons, is that neighborhoods want and need restaurants and dry cleaners and boutiques, grocery stores and gas stations and pharmacies. "But not across the street from their house."

The New Market site has had "many iterations," said Lorna Katz Lawson, zoning and historic preservation chairwoman of the Society Hill Civic Association.

Efforts to change the mix of shops in the 1980s and, later, ambitious plans to build a glitzy hotel and a high-rise failed for many reasons - the economy, timing, incompatibility with the historic district, and management problems.

"The use Toll Bros. has planned now is something everyone is happy about," Lawson said.

There have been quarrels over easements, parking, the kind of materials that will be used on the building facades. But most of the disputes have been settled.

"Everybody is in agreement that having a more permanent population will benefit the neighborhood," Lawson said. "People putting down roots participate in cleanups and activities. Although I am a little cynical because a lot of residential condos in Center City get bought by people who use them as rentals. Still, we need somewhat more population to help support some of the business interests. That's what's always been the problem with that site."

Over on the west end, the feelings are similarly cordial.

"While we would have liked to see a larger retail component integrated into the project along the South Street frontage," David Hess wrote in an e-mail, "we feel that Toll Bros.' new residents will support and benefit from the exciting new and existing businesses."

Hess, vice chairman of the South Street West Improvement District and South Street West Business Association, said the developer's pursuit of projects in the area "shows how desirable the neighborhood has become in recent years."

And so, they are ready to dance.

Contact Melissa Dribben

at 215-854-2590 or mdribben@phillynews.com.