Shares in the FTSE 250 company were down nearly 11% at 77 pence by 0924 GMT.
It said trading at its loss-making United Kingdom and Ireland mobile division had been worse than expected, with sales slumping 20% after it shut stores earlier this year in response to lockdown restrictions and cut jobs.
Adjusted pretax profit for the 53 weeks to the start of May fell to 166 million pounds ($208.81 million) from 339 million pounds last year, despite demand for items such as laptops, networking kits and gaming devices in the lockdown.
Chief Executive Alex Baldock said on a media call this year would be "hard work" but he was optimistic longer term and, as many people carry on working from home and seek to stay in touch despite movement restrictions, technology would be crucial.
"Mobile remains a central category for us in the years ahead," Baldock said.
He anticipated a weakening of overall consumer spending later this year and said turnaround plans would take longer than previously thought.
Dixons, which also trades as Currys and PC World in Britain, said in April it would scrap its full-year dividend.
While it declined to provide a financial outlook, some sector peers have done so. AO World on Tuesday signalled continued growth in online sales.
(Reporting by Pushkala Aripaka in Bengaluru, with additional reporting by Tanishaa Nadkar; Editing by Sherry Jacob-Phillips and Barbara Lewis)
By Pushkala Aripaka