Johnathan Challis-Wagstaff, 24, of St Bernard's Avenue, knew the age of the girl at an early stage in their contact but pursued her regardless.
He made several requests for the child to meet him for sex, which she turned down.
He also asked her to send him indecent images and sent her a video of him performing a sex act on himself, and incited her to perform a penetrative sexual act.
The offences took place between March 3 and March 21, 2018.
Sentencing yesterday (Friday) at Lincoln Crown Court, Judge Martin Hurst said: “You have taken an opportunity to take advantage of a vulnerable girl.
“These offences are so serious, the only option is an immediate custodial sentence.”
Challis-Wagstaff received the 32-month sentence for the two counts of intentionally causing or inciting a girl under the age of 16 to engage in sexual activity.
He had pleaded guilty to this charge and three others at Lincoln Crown Court on December 10.
He has been placed on the Sex Offender Register for life and was given a Sexual Harm Prevention Order for 10 years.
Challis-Wagstaff had originally begun communicating with the girl on Facebook.
Detective Constable Wayne Pilkington said: “Challis-Wagstaff was aware of the girl’s age at an early stage, yet this did not stop him from asking her to send indecent images of herself or inciting her to engage in penetrative sexual act.
“She was also sent images showing him performing sex acts.
“All of the communications between Challis-Wagstaff and the girl were recovered and this provided crucial evidence in this case.”