This note describes how to design a class of benzenoid hydrocarbon radicals, in each of which an unpaired electron of highest occupied molecular orbital (HOMO) is confined locally. Here hexagon-shaped benzenoid hydrocarbons are used as the basic building blocks (units) for the construction of each molecule. This method of confinement is confirmed by the calculations of Huckel MO and of open-shell (SCF) RHF MO with the PPP approximation. (C) 2003 Elsevier Science B.V. All rights reserved.