Diwali (दीपावली पर्व) in Jain Dharma
  Diwali on October 26, 2011:      Vir Nirvan Sanvat 2538
   In Jain Dharma, Diwali is celebration of Tirthankar Mahavira`s contributions to humankind; it commemorates Mahavira`s attainment of moksha or salvation in Bihar`s Pawapuri.
   All  the Jains  celebrate the festival of Diwali with joy.  Diwali or Deepawali is the most important festival in India. For the Jains, it is the second most important festival after the Paryusana Parva. Diwali marks the anniversary of Bhagavan Mahavir's moksha. 
  Diwali festival was first time mentioned  In Harivamsha-Purana written by Acharya Jinasena, in 783AD. Acharya Jinasena  mentions that Bhagavan Mahavira, attained nirvana at Pawapuri  in the month of Kartika,Krashna paksh, during swati nakshatra, at the time of dawn. In Harivamsha-Purana sloka 19 and in sloka 20 he writes  
  jvalatpradiipaalikayaa pravraddhyaa
  suraasuraih dipitayaa pradiiptayaa|
  tadaa sma paavaanagarii samantatah
  pradipitaakaashatalaa prakashate| 19|  

  tatastuh lokah prativarsham-aadarat
  prasiddha-deepalikaya-aatra bharate |
  samudyatah poojayitum jineshvaram
  jinendra-nirvana vibhuti-bhaktibhak |20 |   
    ततस्तुः लोकः प्रतिवर्षमादरत् प्रसिद्धदीपलिकयात्र भारते |
समुद्यतः पूजयितुं जिनेश्वरं जिनेन्द्र-निर्वाण विभूति-भक्तिभाक् |२० |

  The gods illuminated Pavanagari by lamps to mark the occasion. Since  that time the people of Bharat celebrate the famous festival  of "Dipalika" to worship the Jinendra on the occasion of his nirvana.
  In Uttara-puraana written by Acharya GunBhadra (7th or 8th century) it is  mentioned that in the month of Kartika, krashna paksha, svati nakshatra and on the night of the 14th (dawn of the amavasya), lord  Mahavira became a Siddha (attained nirvana).
  An ancient mention of Lord Mahavira's nirvana and lightening of lamps  occurs in Kalpasutra of BhadraBahu, v. 123, "When Lord Mahavira came to Madhyam Pava for his last varshavas, it was the fourth month of the rainy season, seventh paksha, and   krashna of kartik. It was then the last day of krashna of kartik. That night Lord Mahavira attained nirvana." Kalpasutra mentions that due to the presense of gods, the night was  illuminated. It further says "that On the amavasya night, 16 gana-kings, 9 Malla and 9 Lichchhavi, of   Kasi and Kosal, illuminted their doors. They said: "The light of   knowledge is gone, we will make light of ordinary matter".
  Bhagavan Mahavira  discarded the body and the bondage of all Karmas on that night of Diwali, at Pavapuri and attained Mukti or deliverance. Thus we have been celebrating Diwali with lights since the nirvana of  Lord Mahavira.