Celtic aim to complete a loan deal for Borussia Dortmund right-back Jeremy Toljan before the transfer deadline.
Dortmund sporting director Michael Zorc was quoted in the German media as saying his club were still in talks with Celtic over a deal for the 24-year-old.
Celtic have already completed three deals although none of the players will immediately join Brendan Rodgers' squad.
Ukrainian winger Maryan Shved, 21, has signed a four-and-a-half-year deal but will be loaned back to Karpaty Lviv for the rest of the season.
Young American full-backs Manny Perez and Andrew Gutman have both signed deals until 2022 before being loaned to the second tier of United States soccer. USA Under-20 right-back Perez will play for North Carolina and left-back Gutman, 22, who had a trial with Rangers before Celtic moved in, has joined Nashville.
Lewis Morgan moved on loan from Celtic to Sunderland while Rangers midfielder Jordan Rossiter joined Bury on a temporary deal as the Gers tried to close a deal to take pre-contract signing Glen Kamara from Dundee early.
Hamilton made the first signing of the day – St Johnstone striker David McMillan on loan – before appointing Brian Rice as head coach.
And the former Inverness assistant was later reunited with 23-year-old striker George Oakley, who moves from Caley Thistle for an undisclosed fee.
Dundee were busy throughout the day, securing three loan signings – former Dundee United player Ryan McGowan from Bradford, Sunderland midfielder Ethan Robson and Aberdeen winger Scott Wright. Sofien Moussa left and Ryan Inniss returned to parent club Crystal Palace.
Aberdeen reportedly knocked back a major bid from Stoke for defender Scott McKenna while manager Derek McInnes looked to add one player to his squad. The Dons loaned Bruce Anderson to Dunfermline.
St Johnstone signed former Rangers midfielder Sean Goss on loan from QPR and goalkeeper Cammy Bell from Partick Thistle, while Stefan Scougall followed McMillan in departing as he joined Steven Pressley's Carlisle.
Kilmarnock signed 19-year-old Canada striker Liam Millar on loan from Liverpool while Dom Thomas extended his loan spell with Dumbarton.
Hibernian signed Reading striker Marc McNulty on loan after terminating Jamie Maclaren's second spell at Easter Road to allow the Australian to move to Melbourne City. The manager-less club were also linked with a move for Motherwell midfielder Gael Bigirimana.
Livingston loaned midfielder Nicky Cadden to Ayr and manager Gary Holt said: "We have a few irons in the fire, but nothing that is expected."
St Mirren signed 24-year-old Haiti striker Duckens Nazon on loan from Belgian top-flight side Sint-Truiden.
Paris-born Nazon previously had a spell at Wolves and scored 14 goals in total last season on loan with Oldham and Coventry.
Motherwell loaned reserve players Broque Watson and George Newell to East Fife and Albion Rovers while Hearts had the quietest day in the transfer market.
Asked on Thursday morning if there would be any new arrivals, manager Craig Levein said: "No, I'm going to watch Snow Patrol tonight, my phone will be off. Brilliant, eh? I don't see (anyone going out). It will be hard to get hold of me."
