At a party on Thursday night in an East Village bar, Jane Ashe, 71, paired denim pants with a white collared shirt and a blazer. “It’s one party I knew what to wear,” Ms. Ashe said. Heather Frankel, 51, followed a similar formula, but added sunglasses and a top she bought from a thrift store specifically for the event.

They were among the more than 60 people at the Holiday Cocktail Lounge for FranCon, a free event where people dress up in an outfit (denim pants, a blazer and a button-up shirt) that has become synonymous with the writer and humorist Fran Lebowitz.

“If you’re a good New Yorker or if you’re a working New Yorker, you have a button-up shirt, you have a blazer, and you have a pair of jeans,” said Jane August, 25, who created FranCon after reading “The Fran Lebowitz Reader” for a book club in 2021.

For this year’s event, FranCon moved to Manhattan after two years at Blinky’s Bar in Brooklyn. Past FranCons were held on Oct. 27, Ms. Lebowitz’s birthday. This year, the organizers moved it a day earlier to avoid the fuss of Halloween weekend.

The event’s Partiful invite (a digital invitation service that the perpetually offline Ms. Lebowitz likely does not interact with) tallied more than a hundred “going” RSVPs.

The invitation encouraged attendees to partake in a book swap “in the spirit of Fran’s love for books.” For those who don’t smoke cigarettes (a habit that Ms. Lebowitz once told The New York Times that she was “very stimulated” by), candy versions were provided.

Micaela Fagan, 27, a friend of Ms. August who helped organized this year’s gathering (they met at the inaugural FranCon), said dressing like Ms. Lebowitz can allow people to channel her unapologetic nature. It is an armor of sorts that can prepare the dress-alikes for “conversational combat.”

“Fran, as a vehicle, brings together a certain group of people that we want to party with,” she said. “It’s been a queer group. It’s been a really intellectual group. I’m hoping to see people of all different ages today and from all different parts of the city.”

In the darkness of the bar, as “Heroes” by David Bowie blasted through the speakers, clusters of people congregated around each other with drinks from the FranCon menu. Some had names like “Metropolitan Life,” a reference to the writer’s 1978 book, and others were plays on words, like the “Franhattan” and “Lebospritz.”

While some guests chewed on the candy cigarettes, puffs of actual cigarette smoke rose outside the bar. Each person who entered with a blazer was welcomed with a jubilant “Hi, Fran!”

“Immediately, I’m a part of something,” said Ms. Ashe, a retired hospice nurse who has lived in the East Village for more than three decades. “You can just talk to people without feeling like you’re intruding.”

Danny Bellini, 35, who came with his fiancé, Bruxhilda Lumajs, 33, said there were similarities between New York Comic Con and FranCon: how strangers established a sense of camaraderie by way of their outfits.

Known for her sharp, no-nonsense demeanor, Ms. Lebowitz epitomized what some guests described as their idea of a stereotypical New Yorker. Some had not read her work, learning about her through her talks and interviews. For many, including Ms. August and Ms. Fagan, it wasn’t until Martin Scorsese’s 2021 documentary series about Ms. Lebowitz, “Pretend It’s a City,” that they felt a connection to her.

Some attendees said they admired Mr. Lebowitz’s unflinching sense of self or her “realness.” Others, like Ms. Ashe, related to her love of New York. For Ms. Fagan, a comedian and New York City tour guide who grew up in the same New Jersey town where Ms. Lebowitz was born, the writer is a role model.

“We just thought this is so true to our mission in terms of celebrating the old New York,” said Barbara Sibley, the creative director of the Holiday Cocktail Lounge, who spent months corresponding with Ms. August about the event.

Like its namesake, FranCon was not weighed down with any unnecessary flash. The event did not have any speakers or formal activities, and was focused entirely on the interactions between attendees.

Marie Strycharz, 31, who came with her husband, Timothy Cheng, 32, described the event as a space where people can just come and “be a New Yorker.” She added, “We just all happen to have this one shared thing in common and we’re all, like, Franning it up a little bit.”