The first two nonracemic chiral main-chain perylene tetracarboxylic diimide (PDI) polymers have been synthesized via acyclic diene metathesis polymerization. The use of optically pure L-alpha amino acids as the starting materials enables us to tune PDI pi-stacking interaction in optically active polymers. The integration of pi-stack tuning groups renders two main-chain PDI polymers soluble in chloroform. Spectroscopic evidences suggest that PDI pi-stacks form in chloroform solutions of the two PDI polymers, even at very low concentration, probably via an intra-molecular folding process. Inside pi-stacks, PDI units organize in a left-handed helical fashion. Flexible free-standing films can be cast from chloroform solution of one polymer. (c) 2008 Elsevier Ltd. All rights reserved.