A chemical active medium on the base of Belousov-Zhabotinsky (BZ) medi
um was used to design a ''chemical diode''. This system, similar to a
semiconductor diode, shows unidirectional propagation of chemical puls
es and may be possible to be used to construct a massively parallel co
mputational medium. The system of two mesoporous glass plates with fer
roin loaded at the surface was covered by BZ solution and maintained p
ropagating excitation waves. The unidirectional propagation was observ
ed when the plates were placed so that the corner of the one plate was
close to the plane side of the other plate. The study shows that the
important feature of the system is the geometrical arrangement of the
plates and the gap distance between them. Computer simulations confirm
the experimental results.