The heterobimetallic complex [Cu(ii)Mn(iii)(L)2(py) 4](ClO4)·EtOH (1) built using the pro-ligand 2,2′-biphenol (LH2), contains a rare example of a Jahn-Teller compressed Mn(iii) centre. Dc magnetic susceptibility measurements on 1 reveal a strong antiferromagnetic exchange between the Cu(ii) and Mn(iii) ions mediated through the phenolate O-atoms (J = -33.4 cm-1), with magnetisation measurements at low temperatures and high fields suggesting significant anisotropy. Simulations of high-field and high frequency powder EPR data suggest a single-ion anisotropy DMn(III) = +4.45 cm-1. DFT calculations also yield an antiferromagnetic exchange for 1, though the magnitude is overestimated (JDFT = -71 cm-1). Calculations reveal that the antiferromagnetic interaction essentially stems from the Mn(dx2-y2)-Cu(dx2-y 2) interaction. The computed single-ion anisotropy and cluster anisotropy also correlates well with experiment. A larger cluster anisotropy for the S = 3/2 state compared to the single-ion anisotropy of Mn(iii) is rationalised on the basis of orbital mixing and various contributions that arise due to the spin-orbit interaction.