Police say two men approached the victims as they left their cars or garages.
The suspects are between 20 and 30 years old. One is 5-feet 4 inches tall. The other is closer to 6 feet. Both wore dark jackets or hooded sweatshirts.
They were driving a blue or green 4-door Saturn with Indiana license plates.
Police say one man displayed a silver handgun.
Anyone with information should contact Chicago police.