Both incidents happened early Thursday morning.
Investigators say the first incident happened at 2:16 a.m. at the CVS Pharmacy at 2638 East Cumberland Street.
The suspect was in the store for several minutes before bringing a candy bar to the checkout counter.
Police say the man then held out a plastic bag in the shape of a gun and demanded money.
The worker yelled for the manager, and the suspect ran from the store without taking any money.
Then, at 4:00 a.m., police believe the same man entered the Dunkin' Donuts at 717 East Girard Avenue and approached the counter, asking for a doughnut.
As an employee placed the doughnut in the bag, the suspect pulled a bag from his waist and held it as if he had a gun, demanding money.
The worker handed the suspect the cash and the man left on foot.
Police say the suspect is described as white male, about 40 years old standing 5'8" to 5'10" tall and weighing 160 pounds. He had a mustache with a light beard and a thin build. He was wearing a gray hooded jacket, a black shirt, blue jeans, a black knit hat and white sneakers.
Anyone with information is asked to contact Philadelphia Police at 215-686-TIPS (8477), text a tip to PPD TIP (773847) or through PhillyPolice.com.