As it began repositioning Center Plaza, the 1960s-era office and retail building that curls along the top of Boston’s City Hall Plaza, the developer turned some of its vacant office space into an extension of the Boston Calling music festival.

Indie rock bands performed at a VIP party in a former publishing company office on the third floor of Center Plaza overlooking the three-day concert that filled the plaza below with thousands of spectators on Memorial Day weekend.

The connection between hipster bands and commercial real estate might not be immediately obvious, but landlord Shorenstein Properties is taking a creative approach as it repositions the 717,000-square-foot trio of connected commercial buildings it acquired in early 2014 for $307 million. The building now has its own Twitter feed and a new slogan – “The Center of It All” – that reflects the San Francisco developer’s views of the property’s advantages. A reconstructed Government Center MBTA station will reopen early next year, certifying the property’s transit-friendly connections. And Boston Mayor Marty Walsh has gotten a healthy response to his call for ideas to reactivate the 4-acre City Hall Plaza across the street, in a strategy to make the surrounding neighborhood a more attractive place for the public to linger.

“For the past 40 years, it’s been this windswept brick plaza,” said Kevin Kuzemchak, senior vice president for Shorenstein. “But this is a neighborhood that is changing.”

A filing with the Boston Redevelopment Authority is imminent on a $25-million redevelopment of Center Plaza’s gloomy ground-floor retail arcade, currently populated by tenants such as 7-Eleven.

“The plans are going to be a very noticeable level of improvement on the retail arcade,” he said. “We want to take what is now a fairly dark monotonous experience and add new lighting and storefronts where we can, signage, and hopefully install High Line-esque landscaping to the entire arcade and break it up into different zones.”

Office lobbies will be expanded and moved closer to Cambridge Street, Kuzemchak said.

In a second phase of the redevelopment, plans are in the works for additional office space on the roof level, and possibly a roof bar. Shorenstein also wants to activate Pemberton Square – the outdoor space between Center Plaza and the Suffolk Superior Courthouse – with retail shops and food vendors, outdoor seating and new landscaping.

The first major project built by the legendary Boston developer Norman Levanthal, who died in April at age 97, Center Plaza’s occupancy rate is a healthy 85 percent. But creating a hip environment for the next generation of office tenants is important. The Federal Bureau of Investigation will relocate to a new regional headquarters in Chelsea in early 2017 and leave behind 160,000 square feet at Center Plaza.

A New Vision For City Hall Plaza

The plans come as the Walsh administration looks at new ideas for the area surrounding City Hall, which was built in the same era as Center Plaza as part of the massive Government Center urban renewal project.

Critics have long raged against a redevelopment scheme that wiped out the Scollay Square neighborhood and replaced it with severe modernist architecture and a sterile environment, crisscrossed by pedestrians but rarely teeming with street life.

In March, the mayor’s office issued a request for ideas from the public on schemes to activate the plaza, and responses were due in early May. Walsh sought ideas including public-private partnerships to contribute to the vitality of the neighborhood. After the city evaluates the first round of submissions, a more detailed request for proposals is expected to be the next step.

Architects and land-use planners are eager to put their imprint on the space.

Watertown-based Sasaki Assoc. recommended installing pop-up cafes, public art installations, lounge seating and an outdoor market to maximize public involvement.

CBT Architects of Boston looked at successful public plazas such as Montreal’s Place des Festivals for inspiration, said Kishore Varanasi, director of urban planning.

“City hall is generally a tough problem anywhere in the world, not necessarily just Boston,” Varanasi said. “You go there to pay tickets. It’s not necessarily a pleasant and welcoming place, and the plaza doesn’t really add anything to it.”

One thing that Boston City Hall has going for it, though: a central location that, if properly redesigned, could act as a magnet for visitors from busy nearby neighborhoods. CBT’s recommendation includes a large fountain that could be visible from blocks away, acting as a beacon for pedestrians from the West End to Faneuil Hall.

To improve the pedestrian experience, the firm recommended that the various plaza levels be replaced with just two, an upper plateau near Tremont Street and a lower near Haymarket.

“We came away with structural changes to make the plaza welcoming and clear so people could inhabit it on two distinct levels,” Varanasi said.