Significance of Diwali in Jain Dharma

Diwali also called as (deepawali/dipalika)is one the most important festival for jains, as it marks the Nirvāṇa(liberation) of last tirthankara of jainism lord mahavira

Thread on the history & importance of this day since ancient times

In Harivaṃśapurāṇa(7th century)
19th Shloka says that "the gods illuminated Pavanagari by lamps to mark the occasion. Since that time, the people of Bharat celebrate the famous festival of "Dipalika" (splendour of lamps)to worship Lord Mahavira on the occasion of his nirvana."

In Uttara-Puraana written by Acharya Gunabhadra ( 8th century) it is mentioned that in the month of Aaso, krashna paksha, swati nakshatra and on the night of the 14th (dawn of the amavasya), Lord Mahavira became a Siddha (attained nirvana).

Jain inscription such as saundatti in belgaum Karnataka mention about a donation of oil to jinendra worship for Diwali rituals , speaks of "dipotsava"

On this day one of the ardent disciples of Mahavira, "Gandhara Gautam Swami" attained enlightenment on this day. In Mahavira’s absence, he meditated to such an extent that his soul became liberated from all karma. .

On the day of mahavir Nirvana 16 gana kings (mahajanapadas) decided that the light of their masters knowledge should be kept alive symbolically by lighting the lamps , hence entire janapadas where lightened by Diya to mark the auspicious day

The day after Diwali also marks the beginning of the Jain new year , from the day of mahavir Nirvana a new era was started known as the " vira Nirvana samvat"or the "vir samvat"( one of the oldest calendar which is still in use )