  The issue concerning the existence of exact black hole solutions in presence
of non vanishing cosmological constant and scalar fields is reconsidered. With
regard to this, in investigating no-hair theorem violations, exact solutions of
gravity having as a source an interacting and conformally coupled scalar field
are revisited in arbitrary dimensional non asymptotically flat space-times. New
and known hairy black hole solutions are discussed. The thermodynamical
properties associated with these solutions are investigated and the invariance
of the black hole entropy with respect to different conformal frames is proven.
