Both the Premier League and Championship clubs will no longer be able to recruit players for this summer after that date which will see increased business being undertaken over the next few days.
Below are 11 players who have attracted interest during the summer or who could be seen as viable signings for English clubs or those on the continent.
Sam Cosgrove - Aberdeen
A run of 15 goals in 13 games last season helped Sam Cosgrove's reputation massively. When he arrived at Pittodrie he was a very rough talent who need plenty of refinement and polishing. Come the end of the season there was a feeling that those 13 games were simply a purple patch, nothing more. He has hit eight goals in five games with Derek McInnes very keen to hold onto his star striker with interest from down south.
Scott McKenna - Aberdeen
The Aberdeen centre-back has handed in a transfer request which suggests his time at Pittodrie is nearing the end. Wanted by English Championship club, McInnes has admitted that he will face a fight to hold on to the Scotland international but the club want interested side to meet their valuation which is believed to be £7million.
Kristoffer Ajer - Celtic
Linked with a move to AC Milan, the Norwegian is the future of the Celtic defence until he is tempted to a Premier League side willing to part with a substantial fee. Covered at right-back in Europe but is at his very best in the centre. His ability to glide out of defence and open up play is key for the Parkhead side.
Jozo Simunovic - Celtic
Reports suggest that the Croatian could move to Champions League outfit Lille. Six months or so ago he wouldn't have been a huge loss for the side but under Lennon he has built a formidable partnership with Ajer and Celtic are not in the position to let more centre-backs leave.
Callum McGregor - Celtic
As soon as Harry Maguire was on the verge of leaving Leicester City for Manchester United for a huge fee, Brendan Rodgers side were linked with host of players. One of which, unsurprisingly, was Callum McGregor. Lennon has said it before. The last Celtic player he wants to see exit is the midfielder.
Kieran Tierney - Celtic
Celtic fans have had plenty time to come to terms with the possibility that Kieran Tierney won't be at the club for 10 in a row. The left-back is yet to join Arsenal after an on-off transfer saga. And with the transfer window closing on Thursday, belief may be growing that he may just stay which would give the support a huge lift.
Ofir Marciano - Hibernian
Earlier this summer Ofir Marciano gave an interview where he was quoted as saying he wanted a move to "bigger clubs". Hibs were relaxed about the interview and his wife tweeted a picture of Marciano in his kit with three green lovehearts. Little has moved on that front since those quotes and against St Mirren he continued to prove his worth to the club with key saves. It would be surprising if he wasn't being watched by opposition teams and it would be a massive blow to fans of the Easter Road side if he left.
Stephen O'Donnell - Kilmarnock
The Scotland international was tenuously linked with a move to Celtic earlier in the transfer window with people putting two and two together. O'Donnell has entered the finial year of his contract and there was a feeling that Killie may have cashed in on the player. There has reportedly been interest from Championship clubs but the Rugby Park side are in desperate need of reinforcements, not allowing a key player to leave.
Alfredo Morelos - Rangers
The Colombian has an ambition to play in England. But, despite plenty of speculation, Rangers have not had an offer for Morelos. There was chatter of a move to the Chinese Super League but that came to nothing. Holding on to the striker will see Rangers in a strong position with both the South American and Jermain Defoe duking it out for the forward position.
James Tavernier - Rangers
Perhaps Rangers, most important player. His constant raiding down the flanks, plus his set piece delivery, has once again been witnessed this league season already. The right-back has turned himself into a player Premier League teams would consider at Ibrox.
Zander Clark - St Johnstone
Saturday wasn't Zander Clark's finest hour and a half, conceding seven to Celtic, one of which was an awful error. Yet, it would only compound an already disappointing summer if he were to leave McDiarmid Park. The Sants No.1 has been poised to sign a new contract for over a month now.