A copper(I) complex of a 3-(6'-isopropylpyridyl)-substituted verdazyl was synthesized and characterized by X-ray crystallography and magnetic susceptibility. The complex crystallizes in the monoclinic space group C2/c with cell dimensions a = 22.544 A, b = 11.576 A, c = 17.157 A, β = 123.907°, V = 3716.2 A(3). The coordination geometry at copper is distorted tetrahedral, with the two ligand planes separated by 75°. Magnetic susceptibility measurements indicate that the ground state of the diradical is a triplet at this geometry. Fitting to a simple Heisenberg Hamiltonian (H = -JS(1)·S(2)) gave J = 47(1) cm(-1). The triplet ground state results from exchange mediated by the copper ion; in particular, the direction of the distortion from tetrahedral geometry appears to be essential to maintain the high-spin ground state.