Depending on your render engine, see the image below:

                                                                                       

The first node for Firefly can also be used in Superfly.  The Fac channel in the second node controls the amount of blending between the two-color inputs.  Just be aware that the color chips in the Mix node will disappear when texture maps are plugged in whereas the color chips in the Blender node will remain active if you want to tint either one of the inputs.