Sarah Dash, the Trenton-born R&B and pop singer who sang with Patti LaBelle & the Bluebelles in the 1960s and rose to stardom when the group remade itself as the groundbreaking, futuristic funk trio Labelle and scored the international hit “Lady Marmalade” in 1974, died Monday. She was 76.

Ms. Dash’s death was announced in a statement by Trenton Mayor Reid Gusciora. He wrote: “Our resident music legend and Trenton’s very first music ambassador, Sarah Dash, has passed away.” No cause of death was given.

Gusciora cited Ms. Dash’s work this year on a campaign to urge Trentonians to get vaccinated. “Her star will never fade from this city and the heart of its residents,” he wrote.

This past weekend, Ms. Dash appeared with Patti LaBelle during the Philadelphia singer’s concert at Caesars Atlantic City, joining her for “Isn’t It A Shame” from Chameleon, the 1976 album by Labelle, the group she cofounded.

LaBelle posted a video of the two performing and wrote on Twitter: “We were just on stage together and it was such a powerful and special moment! Sarah Dash was an awesomely talented beautiful and living soul who blessed my life and so many others in more ways than I can say. And I could always count on her to have my back. That’s who Sarah was … a loyal friend and a voice for those who didn’t have one.”

Nona Hendryx, the third member of Labelle, who also grew up in Trenton, wrote on Instagram: “Sarah, Nightbird... Words are inadequate so I will use few. We spoke a musical language, music says it best. You, Me, and then You, Me, Cindy and Pat; Bluebelles. Nightbird, why not let heaven be your home.”

Sarah Dash grew up the seventh of thirteen children, and sang in the choir of Trenton’s Pentecostal Trinity Church, where her father was the pastor. She met her first future bandmate when her choir sang at Hendryx’s nearby church.

The two formed their own group, the Del Capris, and merged with two members of the Ordettes — the singer then known as Patricia Holt and Cindy Birdsong — to form Patti & the Bluebelles.

The Bluebelles scored their first hit with “Down the Aisle (The Wedding Song)” in 1963, and followed with “You’ll Never Walk Alone” and “Danny Boy” the next year, recorded for Philadelphia’s Cameo-Parkway records.

“We wore matching dresses and tiaras,” recalled LaBelle in 2008. “We were real prom queens.”

The group encountered racism on “Chitlin’ Circuit” tours of the segregated South, and opened for the Rolling Stones on a U.S. tour in 1965. That association would last decades for Ms. Dash, who sang with Keith Richards on his solo albums Talk Is Cheap in 1988 and Main Offender in 1992 and toured as a member of his band X-pensive Winos.

In England, the group met Vicki Wickham, who became their manager and urged the band to make itself over — after Birdsong’s departure to join the Supremes — as simply Labelle.

The move away from ‘60s girl group innocence began with Labelle in 1971. Ms. Dash — who was briefly married to Philadelphia saxophonist Sam Reed in the late 1960s — and her bandmates wore blue jeans and hung from gymnastics rings on the album cover.

“We were all encouraged to sing out,” Ms. Dash remembered in a 2008 interview with The Inquirer. “Not just little oohs and ahhs, but to really use our voices.”

“It was like we went into a cocoon,” Hendryx said, also in 2008. “And became something else.”

That same year, Labelle recorded Laura Nyro’s Gonna Take A Miracle, working as backup singers on an album recorded at Philly’s Sigma Sound Studios. The trio stepped into its own on early 1970s albums, peaking with Nightbirds in 1974.

By then, Labelle really were something else. The singers wore glittery silver spacesuits and feathered headdresses, and mixed soul, funk and rock, in step with out-of-this-world Afro-Futurists like George Clinton with Parliament-Funkadelic and the Sun Ra Arkestra as well as glam rockers like David Bowie.

Recorded in New Orleans with pianist producer Allen Toussaint and the Meters, Nightbirds became a global sensation thanks to “Lady Marmalade,” the story of a French Quarter sex worker who Ms. Dash and her bandmates gave voice to, en francais: “Voulez-vous coucher avec moi, ce soir?”

LaBelle’s expression of sexual freedom turned them into superstars: They were the first Black pop group to play the Metropolitan Opera House in New York.

Citing the band’s “space time map of sonic starlight,” Adele Bertei writes in Why Labelle Matters, published by University of Texas Press this year, that “theirs was a banquet of Black female rebellion audiences had been waiting to feast on.”

Labelle split a few years after Nightbirds. The breakup was necessary, Ms. Dash said in 2008. “We had to stop ourselves from being a caricature.”

Labelle had a profound impact on rule-breaking women in pop from Madonna to Beyoncé, and “Lady Marmalade” has been covered scores of times, most prominently by Christina Aguilera, Mya, Pink, and Lil’ Kim, for the 2001 film Moulin Rouge.

Ms. Dash’s singular soprano was given the spotlight on a self-titled solo album in 1978, which included the hit “Sinner Man.” She released three more albums in the 1980s, and her “Ooh La La, Too Soon” was used in a Sassoon jeans commercial.

» READ MORE: Back to the belles

Labelle convened again in 2008 for an album called Back To Now, that featured production by Lenny Kravitz and Kenny Gamble and Leon Huff, and a full-fledged tour.

Ms. Dash received a Lifetime Achievement Award from the National R&B Music Society in 2016. Labelle were inducted into the Philadelphia Music Walk of Fame with a plaque placed in the sidewalk on Broad Street in 2017.