The shooting happened around 11:30 p.m. on Sunday in the 7900-block of Halsted Street, police said.
A man, 39, was standing at the Gresham bus turn around when the suspect walked up to him.
The offender demanded the man's items and started shooting when the victim tried to run away.
The victim was shot in the abdomen and back, he was rushed to the hospital in critical condition.
The same shooter then shot a 17-year-old boy who was near the area. He had gunshot wounds to his legs.
No one in custody. CPD Area Two detectives are investigating as an armed robbery.