The first incident happened around 9:11 p.m. on the 4100 block of North Clarendon Avenue in Uptown.
Citing police dispatch reports, three black suspects robbed a customer of his cell phone at 4181 North Clarendon Avenue.
According to online business records, the address belongs to Dollop Coffee and Tea.
Initial reports indicated all three offenders were male, but subsequent information suggest one of the culprits may be female.
After the robbery, a Good Samaritan followed the crooks several blocks south to the area of Addison and Lake Shore Drive, where he lost sight of them, said police.
Approximately thirty-seven minutes later, at approximately 9:48 p.m., a second victim was robbed on the 1400 block of West Thorndale Avenue in the city's Edgewater Glen neighborhood.
Two black males, 5'10 to 6-feet-tall with medium builds, took the victim's iPhone, said police.
Meanwhile, farther south, police apprehended another alleged cell phone thief in Wrigleyville.
The suspect was arrested in an alley behind 3510 North Clark Street, shortly after 10 p.m.
At the time of this report, the muggers involved in the Uptown and Edgewater Glen robberies were still at large.