The Sun says Andre Villas-Boas is close to agreeing a £17million deal for the pair.
Attacking midfielder Halilovic became the second youngest-ever player to take part in a Champions League game last season.
Centre half Jedvaj is an Under-19 Croatia international and made 13 appearances for Dinamo last season. Roma were keen to sign him but could not agree a fee.
Dinamo president Mirko Barisic last night confirmed a deal had been virtually concluded for the pair.