Mr Adityanath and deputy chief ministers Keshav Prasad Maurya and Dinesh Sharma filed their nomination papers in the presence of their cabinet colleagues and senior party leaders, including newly-appointed BJP state unit chief Mahendra Nath Pandey.
Two ministers, Mohsin Raza and Swatantradev Singh, too filed their nomination papers.
According to the Election Commission, scrutiny would be done tomorrow, while the last date for the withdrawal of candidature is September 8. Polling would be held on September 18 and the counting of votes would be done the same day.
The four seats for which by-elections would be held were vacated by MLCs Buqqal Nawab, Yashwant, Sarojini Agarwal and Ashok Bajpai, all from the Samajwadi Party. The fifth seat going to polls fell vacant when Jaiveer Singh, a former BSP legislator, resigned from the party and joined the BJP.
According to senior officials of the UP Vidhan Sabha, the chief minister filed nomination papers for the seat vacated by Mr Yashwant.
Mr Maurya filed nomination papers for the seat vacated by Mr Nawab, while Mr Sharma filed nomination papers for the seat vacated by Mr Bajpai. Similarly, ministers Swatantradev Singh and Mohsin Raza filed nomination papers for the seats vacated by Sarojini Agarwal and Jaiveer Singh respectively.
As the high-profile candidates filed their nomination papers, a large number of MLAs of the ruling party accompanied them and even chanted slogans of 'Jai Shri Ram' and 'Bharat Mata ki Jai'.
Mr Adityanath, who took over as the chief minister on March 19, has to become a legislator within the stipulated six months of assuming office and the deadline will expire on September 19.
Similarly, Mr Maurya, Mr Sharma, Mr Raza and Mr Singh were not members of either of the two Houses of the state legislature. All of them have to get themselves elected to either the Assembly or the Legislative Council before September 19 in order to continue as ministers.
Mr Adityanath and Mr Maurya are presently members of the Lok Sabha.
Yogi Adityanath would become the third successive chief minister after Akhilesh Yadav and Mayawati to adopt the Upper House route.
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