Is there any relationship between carbamazepine and benzodiazepines.

No but yes. They are not in the same class of medications but do have some things in common. Carbamazepine (tegretol) is an anticonvulsant that is also used to stabilize ones mood. It has many off -label uses. Benzodiazepines are anxiolytics which can also be used as anticonvulsants, sedatives & relaxants. So probably the biggest thing they have in common is anti-seizure use.