Five monometallic helical nickel(II) complexes, with various substituents on the pendant arms, were prepared. The crystal structures of three complexes consist of alternating right- and left-handed helical complexes, with intermolecular face-to-face interactions. On the other hand, the other two complexes crystallize in right-handed or left-handed molecules alone, with intermolecular edge-to-face interactions. This behaviour can be correlated with the electron-releasing properties of the substituents on the pendant arms. (C) 1998 Elsevier Science S.A. All rights reserved.