The synthesis and characterization of two types of viologen polymer modification of semiconducting carbon nanotubes (poly-I-CNT and poly-II-CNT) are described. The monomer I is a large three-arm star-shaped compound consisting of three benzyl and three phenyl viologen subunits. Electrochemical polymerization via benzylic radical formation was used. The star arms in poly-I-CNT are well-resolved structures in two-dimensional crystallized fashion (from STM), pointing to self-assembling prior to polymerization. Besides being completely surface covered, individual SWCNTs are interconnected with the polymer in the poly-I-CNT composite material. Poly-II-CNT was prepared by chemical reduction of N′-methyl-N-aminophenyl viologens. Repetitive viologen oligomer brushes are observed along the SWCNT after polymerization. The functionalization is confirmed by XPS, electrochemistry, and Raman spectroscopy.