2-[1-(2,6-Diisopropylphenylimino)ethyl]-6-[1-(pyren-1-ylimino)ethyl]pyridine (L1) and 2,6-bis[1-(pyren-1-ylimino)ethyl]pyridine (L2) were synthesized and used to prepare the corresponding Fe complexes Fe1 and Fe2 from FeCl2. All new compounds were characterized, and single-crystal XRD analysis of Fe1 was performed. The π-conjugated pyrenyl substituent enhanced the catalytic activity of the Fe complexes, which display high activity in ethylene polymerization up to 107 gPE molFe−1 h−1 (PE=polyethylene). These Fe complexes were easily immobilized on multiwalled carbon nanotubes (MWCNTs) through noncovalent π–π interactions. The supported precatalysts showed better ethylene polymerization activity than their homogeneous counterparts to produce well-dispersed MWCNT/PE composite materials.