Inspector V K Deshmukh of Shanti Nagar police station said the incident took place last Monday and the two boys, both aged 16, have been detained.
Victim Bilal Ahmed Ansari (17) was on his way to a public toilet and was intercepted by the two minors who asked him to share the 'beedi' he was smoking, the officer said.
When Bilal refused to share the smoke, the two boys thrashed him up severely, leaving him dead, he said.
Further investigation into the matter is on, police added.