Yes, sort of. DNP doesn’t affect uncoupling proteins directly but it moves protons across the mitochondrial membrane, causing more of the energy to be lost as heat as the uncoupling proteins waste more energy to restore the proton gradient.

There are a bunch of such “protonophores” that move protons across membranes and they are universally toxic if they make it to the mitochondria. I don’t known of any compound that actually mediates the UCPs themselves.