PHILADELPHIA — After leaving the city to travel around the world, Steve Duross came back to Philadelphia in 1991, in the center of what eventually became the city’s “Gayborhood.”

Back then it was gritty and grungy.

In 2004, in the midst of the neighborhood’s transformation, he opened a natural soap and cosmetics store called Duross & Langel, now located on 13th Street, the gay area’s main corridor.

Today, Duross & Langel is just one of many shops on a block booming with bars and restaurants.

From the time Duross moved back to Philadelphia, 13th Street went from a sketchy spot for gays and lesbians to congregate to one of the most popular areas in the city for both tourists and locals. In that way, the block has become a poster child for a new kind of urban renewal in Philadelphia.

As Philadelphia’s economy has struggled to overcome its postindustrial decline, leading it to the unfortunate distinction of “poorest large city in the U.S.,” a new idea has emerged within the halls of city government and the offices of small businesses: Bring in dollars by attracting the broadest possible market — including lesbian, gay, bisexual and transgender people — to the city.

To that end, lawmakers, marketers and LGBT businesses here have been working overtime to ensure that the entire country knows Philadelphia is on its way to becoming “one of, if not the most, LGBT-friendly cities in the world,” as Mayor Michael Nutter recently put it.