Two crystalline complexes, the complex of p-fluorophenylboronic acid with phenyl nitronyl nitroxide (2) and the complex of p-nitrophenylboronic acid with p-dimethylaminophenyl nitronyl nitroxide (3), were prepared. Both of those nitroxide (1) exhibit ferromagnetic spin interactions (1 : J/k(B) = +0.65 K, 2 : J/k(B) = +0.58 K, 3 : J/k(B) = +1.35 K). The results are discussed based on the X-rap crystal structure.