A couple of naphthalenediimide 4 and 5 and series of perylenediimide derivatives 6–9 carrying TEMPO radical were prepared and their redox, FET, and magnetic properties were investigated. The radical compounds 4 and 6–9 were found to show antiferromagnetic interactions obeying the Curie–Weiss model, while the naphthalenediimide derivative 5 exhibited a singlet–triplet magnetic behavior and it could be well understood by the short ...