A 24-year-old man was assaulted as he bought cigarettes in the Premier shop, Silver Street, Kettering, on Friday, 19 June.
The man was in the shop between midnight and 12.20am when he was approached by two men who punched him in the face.
The victim sustained a significant facial injuries and concussion as a result of the assault.
Both offenders were white, slim and about 23-years-old, with one of the offenders having blonde hair.
Police would like to speak to anyone who may have witnessed this incident and anyone who may have any information about it.
Witnesses or anyone with information is asked to contact police on 101 or Crimestoppers anonymously on 0800 555 11