Dashrath Singh Shankwar (Samyukt Samajwadi Dal) and Sanju Katiyar (independent), both withdrew from the fray today, District Electoral Officer Selva Kumari J said.
This leaves the field clear for 35-year-old Dimple, fielded by the ruling Samajwadi Party.
The election commission has been informed about it and a formal announcement would be made only after its approval, Selva said adding that tomorrow is the last date for withdrawal of names.
After Congress and BSP decided against fielding their nominees and the BJP candidate failed to file his nomination papers at the last minute, Dimple was expected to get a walkover on the seat vacated by her husband Akhilesh Yadav when he became the chief minister and was elected to the Legislative Council.
She filed her nomination papers on Tuesday.
She had suffered a humiliating defeat at the hands of Congress' Raj Babbar in the by-polls for the Firozabad Lok Sabha seat in 2009.
The Congress had opted not to contest the election in Kannauj saying it did not field its candidate even in 2009 elections and the BSP had decided to keep away from the bypoll alleging the ruling party of continuing with its tradition of nepotism by fielding Dimple.