Manganese based oxides are of great interest for both spintronic and multiferroic applications.Pb2MnO4 crystallizes in the acentric but non-polar space group P-421c which allowspiezoelectricity. Pb2MnO4 shows antiferromagnetic order below TN = 18K. The magnetic spacegroup P-421c is compatible with piezomagnetism making Pb2MnO4 a candidate multipiezo(piezoelectric and piezomagnetic) material. However it is difficult to make dense Pb2MnO4 pelletsfor piezo- properties study. We have prepared a new solid solution Pb2-xBixMnO4 (x = 0 - 0.3). Bisubstitution significantly improves the sintering properties and dense pellets have been obtainedfor piezo- studies. We propose a powder neutron diffraction study on Pb2-xBixMnO4 at 5 - 300 Kon WISH to refine the magnetic and crystal structures, and detect any subtle magnetostrictioneffects from coupling between them.