Brentford have signed Jose Peleteiro Ramallo, known as Jota, from Celta Vigo for an undisclosed fee and Jon Toral on a year-long loan from Arsenal.
Both are Spanish attacking midfielders and Jota, 23, has signed a three-year contract at Griffin Park.
Toral, 19, was with Barcelona before joining Arsenal in 2011.
"Jota is a very talented left-sided player. He is very highly regarded in Spain. He offers us real technical craft," said Bees boss Mark Warburton.
"It is exciting for Brentford to attract players of this stature. There was a lot of interest from clubs in La Liga and the Championship."
Jota played four times for Celta's first team and also had a loan spell at Real Madrid B.
He spent last season on loan with Eibar and scored 11 goals in 35 games as he helped them win promotion to La Liga.
The versatile Toral can play on either flank as well as in the centre of midfield.
Warburton said: "Jon has come through a couple of nasty injuries. It is great to see him fully fit and he can now start to show his undoubted potential."
Meanwhile, Bees forward Montell Moore, 18, has signed a new three-year contract.