The Ibrox club held an interest in the goalkeeper last season, with Martin interested in bringing in a shot-stopper to compete with Jack Butland for the No1 spot.
Carl Rushworth, who earned promotion to the Premier League with Coventry, was an option, with Charles also targeted as a possible Ibrox arrival under Russell Martin.
However, neither would be signed by Rangers with Butland keeping the gloves and Liam Kelly acting as his back-up, coming in for a handful of matches last season.
Now, though, Charles has completed a stunning move to Premier League giants Manchester City.
The goalkeeper, 20, has signed a five-year contract with City but has immediately left the club to sign for Queens Park Rangers on loan for the season.
It's thought Man City have paid £3m to sign Charles from Sheffield Wednesday, but the fee could surpass £10m should add-ons fees be met during his time at City.
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On his return to City, where he came through the academy, Charles commented: “To be back at Manchester City is a very special and proud moment both for me and my family,” he said.
“I know first hand what a special club City is and I am so excited about looking to the future.
“City take the development of young players very seriously so I know that my loan to QPR will only help me grow and improve as a player too.
“I’ll now give everything I can for a successful season in the Championship before hopefully returning to Manchester a better goalkeeper.”
Man City director of football Hugo Viana added: “Pierce is someone whose progress we have been following closely, and we are delighted to welcome him back to Manchester City.
“Pierce has already learned a lot during his time at Sheffield Wednesday but is still very young and hungry to now further progress and develop.
“He also knows the Club and is very much aligned with the values we all share.
“We are very happy to have secured Pierce’s signing and are excited to now help in his future career development.”