In each incident, people entered a mobile phone store, implied they had a weapon and took items by force, Chicago police said.
The first robbery was reported about 4:15 p.m. March 23 in the 3800 block of West Roosevelt Road, police said.
The second robbery happened about 10:30 a.m. April 2 in the 2300 block of West Cermak Road, police said.
The robbers are believed to be between 25 and 30 years old and 5-foot-6 to 6-feet tall.
Anyone with information is asked to call Area Four detectives at 312-746-8253.