Reference: Silsilah Fataawa Noor ‘alad-Darb – Tape 376
Question: O Shaykh, when the imaam sits between the two khutbahs, is there a specific supplication the congregation should make?
Response: No, there is no specific supplication [legislated], however, it is befitting that one seizes the opportunity at this time to supplicate [to Allaah]. That is because it is most probable the ‘hour of acceptance’ [for any supplication] on the day of Jumu’ah is between the time the imaam arrives [for the khutbah] until the [actual Jumu’ah] prayer starts.