[1] Nikolay Mladenov was one of the two Bulgarian politicians exposed in the Pandora Papers, together with oligarch Delyan Peevski sanctioned under the Magnitsky Act.

Mladenov denied any wrongdoing and claimed he simply founded an offshore firm to develop a consultancy practice before his involvement in the UN.

[10][11] At the time, the country security had deteriorated as Sunni Islamist groups stepped up an insurgency against the Shi'ite-led government.

[12] On 5 February 2015, Mladenov was appointed United Nations Special Coordinator for the Middle East Peace Process, replacing Dutch diplomat Robert Serry.

[14] In 2016, he led efforts of the Quartet on the Middle East on issuing a report on concrete steps that could at least preserve the possibility of a two-state solution.

[15] In late 2018, Mladenov was mentioned in news media as potential successor of Staffan de Mistura as United Nations Special Envoy for Syria.

[17] In December 2020 the Security Council approved United Nations Secretary-General António Guterres's proposal to appoint Mladenov as the new UN envoy for Libya.