The National League pair both progressed over the weekend – both going through by way of penalty shootouts.
The Moors fell behind to Lowland Football League side Kelty Hearts, but Matt Stenson’s second half leveller forced the tie to spot kicks.
Terry Hawkridge, Alex Nicholls and Mitch Hancox all netted for Tim Flowers’ side – leaving captain Darren Carter to slot home the fourth and winning penalty.
Elsewhere, Josh Bickerstaff opened the scoring at the Racecourse before Wrexham were pegged back four minutes from time by Ayr United.
In the shootout, with the score level at 5-5, Luke McCowan missed for the visitors leaving Jake Lawlor to slot home the winning penalty.
In this afternoon’s draw, Solihull Moors will face either Ballymena United or Rangers Colts at Damson Park while Wrexham will enjoy home comforts again when St Mirren Colts travel to North Wales.
Ties will be played on the weekend of October 13/14.
Scottish Challenge Cup Fourth Round draw:
Solihull Moors v Ballymena United or Rangers Colts
Wrexham v Saint Mirren Colts