Liverpool have sold midfielder Marko Grujic to Porto for £10.5m and forward Taiwo Awoniyi to Union Berlin for £6.5m.
Nigerian Awoniyi, 23, scored five goals in 22 games on loan at German side Union Berlin last season.
Liverpool have negotiated 10% sell-on clauses in both deals.
Grujic became Reds manager Jurgen Klopp's first signing at the club when joining from Red Star Belgrade in January 2016 for £5.1m.
He made 16 appearances for Liverpool, while also spending spells on loan at Cardiff City, Hertha Berlin and Porto.
Awoniyi, who joined Liverpool in August 2015, did not feature for the club and was only granted a work permit to play in the UK in May.