A novel lanthanide(iii)-nitronyl nitroxide chain {[Gd(hfac)3(Nit-Ph-3,5-bIm)(H2O)]·C4H10O}n (1) was prepared and characterized. Strikingly, an unexpected ferromagnetic coupling between the Gd(iii) ion and the nitroxide group mediated by hydrogen bonding has been observed for the first time.