Striker Ashley Grimes grabbed a late winner to send Port Vale tumbling to a 1-0 defeat.
Grimes found the net three minutes from time when he fired in from 10 yards after a surging run from Josh O'Keefe opened up the Vale defence.
The result lifted Lincoln clear of the relegation places giving manager Steve Tilson his third win in eight days.
Lincoln fully deserved the points against an out of form Vale team that rarely threatened. Lincoln had the best chances and went close to taking the lead when Grimes got into a good position only to see his shot blocked by John McCombe.
City's veteran striker Delroy Facey then tried an effort from 30 yards which beat the keeper but ended up on the roof of the net.
Vale's Justin Richards had a couple of efforts late in the second half but did not trouble City keeper Trevor Carson. O'Keefe almost broke the deadlock in the 78th minute when his low shot smashed against the post as Lincoln kept on top.