Does Unity support lists of lists?

A fairly straightforward question: does Unity support lists which contain lists? I've tried this in Boo, but to no avail (though it may be a syntax error) and was wondering if it is supported at all in Unity?

And if it doesn't, are there any workarounds? I'm trying to make a simple data structure to store coordinates of pieces on a playing board. A list of lists would allow me to say board[3][7] = 'queen' for instance.