Jeremy Ou

robp_sidefx
While each has its pros & cons, there are (at least) three ways to achieve this:

1 - Scene Import will handle SOP-level material assignment

2 - SOP Create wraps SOP Import and has a Materials tab with an "Auto-fill Materials" button (note it's a one-off, not a live-updating thing)

3 - The "Auto-fill Materials" button mentioned above is a Python scrips inside the SOP Create HDA which you could try extracting and running in a Python LOP