<p>Why does a Boolean consume 4 bytes and a char 2 bytes in the .NET framework? A Boolean should take up 1bit or at least be smaller than a char.</p>

It is a question of memory alignment.  4-byte variables work faster than 2-byte ones.  This is the reason why you should use int instead of byte or short for counters and the like.
You should use 2-byte variables only when memory is a bigger concern than speed.  And this is the reason why char (which is Unicode in .NET) takes two bytes instead of four.