Mojo, a music brand and concert organizer, was founded in 2021 by Charley Blacker, Alex Parker, and Emily Donovan while they were students at the University of Massachusetts Amherst. The trio of friends decided to create Mojo out of their shared love for music and house shows.

“We saw there were so many local musicians that were so talented, but they didn’t have the platform we thought they really deserved,” Blacker told the Globe during Saturday’s festivities. “So we thought if we could do the behind-the-scenes work of organizing photographers and [provide] a social media platform, we could give these musicians the platform they deserve.”

Five years later, the team behind Mojo is sticking to their mission, tackling their biggest venue yet with this weekend’s event at City Hall Plaza, which previously served as the original location for Boston Calling before it moved to the Harvard Athletic Complex in Allston. Boston Calling announced last year that it is taking a one-year hiatus in 2026, with plans to return in 2027.

In addition to getting the chance to work on such a big event with his best friends, Blacker hopes Mojo Boston can help “lead to a lot more opportunities for local music.”

There was a wide range of genres represented at Saturday’s event, from the pop-rock stylings of The Bends to house and garage music from DJ AC Slater. Prior to the Boston debut, Mojo brought a festival to Pennsylvania’s Happy Valley in April and returned to Amherst later that month to host another event.

Mojo Boston attendees and former UMass Amherst students Emily Bowler and Max Debeau have been familiar with Mojo since its inception, watching the organization go from hosting basement shows to full scale music festivals. Debeau noted how many of the acts at Saturday’s event have worked with Mojo in the past, performing at UMass and other shows around the Bay State.

“To see it all come together has been great,” Debeau said. “This is the stage that they all deserve.”

“It’s crazy how quickly they were able to erect something so amazing,” Bowler added.

Formed in New Bedford, the band Autumn Drive was one of 18 acts that performed at Mojo Boston, and they are no strangers to a Mojo show.

“We’ve done, I think, every single Mojo that there is, so we’re very tight with them,” said guitarist and singer Charlie Gamache. “When we found out they were doing a big festival [in Boston], I was like, ‘We want in no matter what.’”

The band emphasized how much their relationship with Mojo has meant to them over the years, with Autumn Drive drummer Joe Gauvin praising the organization for “always putting us in front of a crowd that’s there to see music and hear us.”

From a makeshift stage out of wooden pallets in his basement to Boston’s City Hall Plaza, Blacker is is proud of Mojo’s success and is already looking ahead at what’s to come.

“This is really just the start of it all,” said Blacker. “We have very lofty ambitions and goals, and we have nothing but confidence in our ability to accomplish everything we set out to do.”

Gitana Savage can be reached at gitana.savage@globe.com. Follow her on X @gitana_savage.

The new policy requiring anyone under 18 to be accompanied by someone over 21 in Market Square may not be as firm as some first thought. 

KDKA observed unaccompanied kids in and around the square in Pittsburgh on Saturday evening, but in very small numbers, especially compared to the hundreds of kids who gathered as recently as during the NFL draft last month. Many of the kids were walking through the square or to restaurants like Chipotle. 

It was the kids who lingered on Saturday evening who were approached by either youth outreach teams, private security or officers. 

Von Madden — the founder of AIM, a youth outreach group — said it’s when kids start gathering in large numbers that they’ll be asked to leave. 

“I don’t think they are going to be kicked out of the space for buying food or walking by,” Madden said. “The policy was so they’re allowed to hang out, but if they’re causing disruption, they were asked to move.”

Outreach workers within the square on Saturday evening said they’ve been approaching kids to make sure they are aware of the rules, but aren’t forcing them to leave. Some workers suggested alternative places they could go, as they work to form relationships with the kids

Madden, who was not at the square on Saturday, said in theory, enforcement works by private security engaging kids first, and then if that doesn’t work, outreach staff comes over. Only as a last resort are police officers brought in.

KDKA watched as a group of about 15 to 20 kids formed along Market Street steps away from a police SUV on Saturday evening. A member of the private security approached the kids first, pointing toward the exit of the square. Once more kids gathered, a group of five to 10 officers walked over, and the group dispersed toward Liberty Avenue. 

A group of teenagers near Chipotle told KDKA that officers told them they had to leave if they weren’t actually going to the restaurant. Madden said the policy, which is in effect from Thursday to Sunday from 3 p.m to midnight, has worked well this week.

“It was phenomenal. Thursday was great,” Madden said. “The kids came, a lot of kids. They were absolutely excited about everything going on.”

Thursday was the first night for the temporary roller rink in Market Square, and a rainy Friday kept many people away. People enjoying their Saturday evening in the square gave mixed reviews about the policy.

“I think it’s definitely necessary,” Cristina from Butler told KDKA. “It keeps the community safe, and it allows adults and parents to know that their kids are safe as well, and just a more controlled environment.”

Danielle Graham from Robinson said she’d been observing kids interacting with police and believes kids aren’t welcome in Market Square, even if they are not being disruptive. She said there was a discrepancy in what private security and officers knew about the rule, adding that police asked her if the child she was chaperoning was her legal guardian. 

She said she offered to chaperone kids to allow them to enjoy the square and so she could observe what was going on. 

“There’s no clear understanding from the people that are supposedly enforcing it,” Robinson said. “You just put more vulnerable kids in front of law enforcement, things can go wrong.”

Pittsburgh City Councilwoman Barb Warwick shared her own criticism of the policy during a meeting last week.

“Not only does this feel highly unwelcoming to families with teens, it also seems questionable in terms even of enforcement,” Warwick said. “I don’t know that there’ll be like a private security, what are we checking IDs like, you know? How is this working? My understanding is it’s on an event permit.”

KDKA-TV did not observe any IDs being checked on Saturday and saw at most 12 officers in the square at once, along with the private security.