Large pore aluminophosphate-based molecular sieves, MgMnAPO-5 and MnZnAPO-5, were synthesized by hydrothermal methods. The samples were characterised by the techniques of XRD, FT-IR, P-31 and Al-27 MAS-NMR spectra, BET-surface area, n-butylamine-TPD and ICP-MS chemical analysis. The catalytic performance of these materials has been examined for ethylation of benzene with ethanol in the vapour phase. The products were ethylbenzene, p-diethylbenzene, m-diethylbenzene, o-diethylbenzene and PAB[(1,2,4 and 1,3,5-triethylbenzene) and (1,2,4,5-tetraethylbenzene)]. Maximum conversion (20.6%) was observed at 400degreesC over MnZnAPO-5.