As far as I know, a bishop and queen can't force a checkmate by their own (if the king starts from the ideal position and plays the best moves), so your king's help is needed. I might be remembering this wrong, though, so don't trust me.
However, when you have another pawn, the easiest way to mate is simply promote it and mate the king with two queens.
From your initial position play: Ba6, Bc8, Ba8.
King has one move: Kb8.
Mate with the queen: Qb7++
perfect tysm!!!
Also try this site for studying all kinds of simpler endgame situations.
http://www.k4it.de/index.php?topic=egtb&lang=en
Edit:
I should note for completion's sake, that one of my criteria for my post #6 diagram was that the white king should not be involved, (either moved, or used for "herding" in any way). Just now, I checked my mating pattern by entering my original situation in the above database link, and they offered multiple paths, the least of which was a mate in 6, but such involved white's king. No mate shorter than 7 was offered for a pure queen + bishop vs lone king from my starting situation, and my pattern was indeed among them. I am not bragging so much as claiming that it is simple when the general patterns of herding are known. More efficient mates involving white's king were trickier.
Well... seems like you're not looking to where you want to go, so it's no wonder you can't get there.
Notice to mate with a queen and any piece you want her in front of the enemy king (not on the edge of the board, and not diagonally).
So move your bishop to a square that controls a square in front of the enemy king, then move your queen to that square. As you saw random checks don't make a mate magically appear :p
As far as I know, a bishop and queen can't force a checkmate by their own (if the king starts from the ideal position and plays the best moves), so your king's help is needed.
Actualy Q+B can easily force checkmate without royal help. It is trivial to drive the bare King to any corner you want with just Q: stand a Knight's jump away from him in the opposit direction, and just mimic his moves. (Be sure the Bishop is out of the way, not attching any squares in the sector you confined the King to, to prevent accidental stalemates.) Of course you have to stop that once he is restricted to 2 squares, say a1 and b1 (so Q on d2). Then use your Bishop to check him on a1 (over b2), or attack a2 while he is on b1, and the next move you can mate him with Qb2# or Qa2#.
This works pretty much for Q + any piece. The only resriction is that the piece should be able to attack one of the squares next to the King, to protect the Queen there when she delivers checkmate. So you can also use it as a strategy for K+Q vs. K: drive wth Q to the corner first, and only then start approaching with the King.
From your earlier position:
The solution posted by pava is flawed.
1.Ba6 Kb8
2.Qb7#
here is a Queen-Bishop CheckMate:
simples!
Hello all, i just had a very frustrating game, where after outplaying my opponent down to just his king, i still had my queen, light-squared bishop, and a pawn free to run. Ive been in this situation before where the other person doesnt resign, and instead tries to exploit my lack of knowledge to make me stalemate him. I did not want this to happen again, so after corning his king and him dancing around my bishop on the dark squares like so:
i decided to run away and just queen my pawn to be safe. This is however, very embarassing and if i had to do this in a tournament i would feel quite foolish. Can someone post a queen bishop checkmate? Kings help is fine