A new class of integrals
involving the product of Ξ-functions associated with primitive Dirichlet characters
is considered. These integrals give rise to transformation formulas of the
type
where αβ = 1. New character analogues of the Ramanujan–Guinand formula, the
Koshliakov’s formula, and a transformation formula of Ramanujan, as well as its
recent generalization, are shown as particular examples. Finally, character analogues
of a conjecture of Ramanujan, and Hardy and Littlewood involving infinite series of
Möbius functions are derived.