The terdentate anionic picolinate-based nitronyl nitroxide (picNN) free radical forms neutral and robust homoleptic complexes with rare earth-metal ions. The nonacoordinated Tb3+ complex Tb(picNN)(3)center dot 6H(2)O is a single-molecule magnet with an activation energy barrier Delta = 22.8 +/- 0.5 K and preexponential factor tau(0) = (5.5 +/- 1.1) x 10(-9) s. It shows magnetic hysteresis below 1 K.