"It will be one of the most difficult public days so far," Imette's grieving mother, Maureen, said of the graduation, which she will attend with her daughter, Alejandra.
When Imette's name is called, Maureen and Alejandra St. Guillen will walk across the arena's stage to accept her degree in forensic science before more than 7,000 students, alumni, faculty and guests.
"I have always been so proud of Imette and all her accomplishments and how she worked so hard to get everything she earned," said Alejandra, 29, choking back tears.
"I can't imagine not being there.
"It is going to be hard, but we are looking forward to it," she added, recalling how she preceded her younger sister to the Big Apple and graduated from City College.
"There will definitely be a mixture of the pride we feel about Imette and the sadness that we have experienced," said Maureen St. Guillen.
"It is a sad time for us, but obviously, we will be there."
Imette, 24, was abducted and brutally murdered Feb. 25 — allegedly by ex-con Darryl Littlejohn, 41, who had been hired illegally as a bouncer at The Falls Bar in SoHo. Her naked body, wrapped in a blanket and tied with clear packing tape, was found later that day in a desolate section of Brooklyn.
College President Jeremy Travis recounted how the slaying of the vibrant dean's-list student "rocked" the college community, which has been grappling with her tragic loss and trying to find appropriate ways to honor her life.
"It will be a very poignant moment inviting Imette's mother and sister to the stage," Travis said.
"We were all touched by Imette's horrific murder, and we have been struggling to honor her memory.
"This is a fitting way to end the semester by awarding her diploma to her mom and sister in front of all the graduating students," he added.
"It is a gift from us to the St. Guillens, who are just such inspirational people."
Following the ceremony, family lawyers, Joseph Tacopina and Rosemarie Arnold, have arranged for mother and daughter to meet with legislators here to discuss their campaign to strengthen laws that should have prevented Imette's death.
They hope new legislation will spare other families from a similar tragedy.
The state Liquor Authority charged the bar where St. Guillen was last seen alive with a slew of violations, including misleading cops and knowingly employing a felon.
The St. Guillens will also attend on Sunday the ceremony awarding the first scholarship named in Imette's honor.