Bradford had another chance in the 24th minute when Omar Daley, back after injury, fired in a low cross but Gareth Evans put the ball wide from close in.
The Bantams were made to pay on the half-hour when Lincoln went ahead with a well-worked goal. Delroy Facey flicked on for Brian Gilmour, and his neat pass was converted by Chris Herd.
Seven minutes later Bradford's fragile defence cracked again with Facey putting Gilmour clear. The Scot held off three defenders before placing his shot into the net.
It was only after the introduction of sub Michael Boulding at half-time that the visitors posed any real threat and they pulled a goal back when Lincoln failed to clear a cross from O'Brien and Boulding fired in.
Source: Team Talk