Prabodhini Ekadashi also known as Devotthan Ekadashi, is the 11th lunar day (ekadashi) in the bright fortnight (Shukla Paksha) of the Hindu month of Kartik. It marks the end of the four-month period of Chaturmas, when god Vishnu is believed to sleep. It is believed that Vishnu sleeps on Shayani Ekadashi and wakes on Prabodhini Ekadashi, thus giving this day the name “Prabodhini Ekadashi” (“awakening eleventh”), Vishnu-prabodhini (“awakening of Vishnu”) and Dev-Prabodhini Ekadashi, Deothan, Dev uthav ekadashi or Dev Oothi ekadashi (“god’s awakening”). The end of Chaturmas, when marriages are prohibited, signifies the beginning of the Hindu wedding season. It is also known as Kartiki Ekadashi, Kartik Shukla ekadashi and Kartiki. Prabodhini Ekadashi is followed by Kartik Poornima, which day is celebrated as Dev Diwali or Diwali of gods.
It is also believed that Lord Vishnu married to goddess Tulsi on this Day.
A fast is observed on Prabodhini Ekadashi and the ritual marriage of the Tulsi plant is performed with god Vishnu, in the form of the holy black colored Shaligram stone, which is regarded as the husband of Tulsi, in its twenty four permutations. During evening time people prepare floor designs by geru paste( red soil) and rice paste which is a very well known tradition. Images of Lakshmi and Vishnu are also prepared from it. Lakshmi pujan and Vishnu pujan is observed at evening time with sugarcane, rice, dried red chillies, etc. And, is then given to pandits. This ritual marriage is known as Tulsi Vivah and may be conducted on the next day of Prabodhini Ekadashi instead of Prabodhini Ekadashi itself.