Changing material properties at runtime

Is there any way to make a new (unique) material at runtime, modify it, and then assign it to a renderer's material (in that order) rather than the usual method of modifying a material already attached to a renderer? I need to do it in that sequence given the way my code is set up; but It doesn't work if I change the properties on the new material itself but only if I change it on the material assigned to a renderer, such as the following code:

Code (CSharp):

1. rend.materials[j].SetFloat("_StencilRef",Frequency);

But the following doesn't work:

Code (CSharp):

1. NewMaterial.SetFloat("_StencilRef",Frequency);

I remember reading somewhere that this is expected behavior; but is there an alternate way to do it?

 

There must be a way to just modify the properties in a new material variable before applying the material to the renderer, but I can't get it to work. Anyone know?