[3] Molchanov reached his first ATP doubles final at the 2018 Swiss Open in Gstaad partnering Igor Zelenay.

At the 2022 Melbourne Summer Set 1 Molchanov reached the semifinals partnering Ričardas Berankis losing to sixth seeds Aleksandr Nedovyesov and Aisam-ul-Haq Qureshi.

At the 2022 Open 13 Molchanov won his first title partnering Russian Andrey Rublev in Marseilles.

He reached his third doubles final at the 2023 Stockholm Open and won his second title with Andrey Golubev.

[6] In February 2015, he faced never confirmed or investigated allegations of match-fixing after suspicious betting patterns and unforced errors were noticed during a defeat to Agustín Velotti.