So I got my NES to USB adapter in the mail today. I had fun playing it with my NES emulator. Then I thought, could I use this thing to play Mednafen in Virtual Boy mode? It’s the same controller plug in, though I doubt the pin outs are the same. I wonder if it would work, but I don’t want to break the thing.

Yeah, no, it wouldn’t be worth the trouble at all. 1) it’s not the same connector, just very similar, and 2) unless you can see more of them in the Windows control panel, it most likely only supports eight buttons, so you’d only get the left d-pad, start, select, and two of the right d-pad directions (left and down, I believe). Even if they used the chip from an SNES pad adapter, you still wouldn’t get B and A.