Answer

Bhagwan Neminath’s Moksha Kalyanak is on Ashadh Krishna Ashtami (Ashadh Krishna 8). ( jainworld.jainworld.com)

Explanation

A Jain history source states that Lord Neminath attained liberation at Mount Girnar on Ashad Krishna 8, and that this day is celebrated as His Moksh Kalyanak. ( jainworld.jainworld.com)

Takeaway

So the tithi is Ashadh Krishna Ashtami. ( jainworld.jainworld.com)