The collision, reported to police at 3.14pm yesterday (March 1), happened on Pilham Lane, between Pilham and Corringham, off the A631, east of Gainsborough.
It involved two vehicles: a white Ford Transit van and a grey Mini Cooper.
The driver of the Mini, a man in his 50s from the Scunthorpe area, died. Both the driver and passenger in the van sustained minor injuries.
A police spokesman said: “We are now seeking any witnesses, or those with dashcam footage, to contact us.
"In particular, we are aware of an HGV driver who stopped at the scene and who may have dashcam footage, but who left before police arrived.
"This driver may hold important information that could help our investigation.”
If you can help us, please contact 101 quoting Incident 227 of 1 March, or email [email protected]