The stylish sisters attended a Generation NXT Dream Foundation benefit event at 1 Oak in New York City on Sunday evening.
Kim opted for a cleavage-baring black sheer Stella McCartney top, a Lanvin black skirt, a Tom Ford jacket, stockings from the Kardashian Kollection and Tom Ford heels. Kourtney donned a crisp white pantsuit with black pumps and Khloé sported a blue jumpsuit with black detail and snakeskin heels.
"Up in the club #NYCNights," Kim Instagrammed a collage-style snapshot, featuring the sisters as well as pals Jonathan Cheban, Rachel Roy and Simon Huck.
The E! stars then went to Tao downtown, a source reveals to E! News. Kim left early to meet up with fiancé Kanye West, but Kourtney and Khloé kept the party going and stayed out until 2 a.m. The gals were "really happy" and were "holding hands, hugging and smiling a lot."
After their night out on the town, the ladies were spotted shopping on Monday, while cameras rolled for Keeping Up With the Kardashians.
—Additional reporting by Michelle Falls