Communication: The NO ... HOB hydrogen bond has recently been shown to play a role as an intermolecular ferromagnetic spin coupler. Studies of this bond in phenylboronic acid derivatives substituted by the nitronyl nitroxide radical moiety are presented, in particular the synthesis, crystal structure, and magnetic properties of the para-substituted phenylboronic acid shown in the Figure and the corresponding meta compound. Boronic acid derivatives bearing the NO radical center are shown to be promising precursors for molecular magnetic materials.