Complexation of nickel(II) bromide with tertbutyl 5-phenyl-2-pyridyl nitroxide (phpyNO) gave two morphs of doubly chelated [Ni(phpyNO)(2)Br-2] as a 2p-3d-2p heterospin triad. The alpha phase crystallizes in the orthorhombic space group Pbcn. An asymmetric unit involves a half-molecule. The torsion angle around Ni-O-N-C-2py is as small as 6.5(3)degrees at 100 K and 7.0(6)degrees at 400 K, guaranteeing an orthogonal arrangement between the magnetic radical pi* and metal 3d(x2-y2) and 3d(z)(2). orbitals. Magnetic study revealed the high-spin ground state with the exchange coupling constant 2J/k(B) = +288(5) K, on the basis of a symmetrical spin Hamiltonian. The beta phase crystallizes in the monoclinic space group P2(1)/n. The whole molecule is an independent unit. The Ni-O-N-C-2py torsion angles are 24.2(6) and 37.2(5)degrees at 100 K and 10.4(7) and 25.9(6)degrees at 400 K. A magnetic study revealed a very gradual and nonhysteretic spin transition. An analysis based on the van't Hoff equation gave a successful fit with the spin-crossover temperature of 134(1) K, although the susceptibility did not reach the theoretical high-spin value at 400 K. Density functional theory calculation on the beta phase showed ground S-total = 0 in the low-temperature structure while S-total = 2 in the high-temperature structure, supporting the synchronized exchange coupling switch on both sides. Consequently, the beta phase can be recognized as an "incomplete spin crossover" material, as a result of conflicting thermal depopulation effects in a high temperature region.