Crystalline aluminophosphates and related compounds having in the as-synthesized dried form the chemical composition expressed asaR(bP.sub.2 O.sub.5)(cAl.sub.2 O.sub.3)(dSiO.sub.2)(eMeO)(zH.sub.2 O)wherein R represents a diamine of the general formulaR.sub.2 R.sub.3 N--R.sub.1 --NR.sub.4 R.sub.5wherein R.sub.1 represents a C.sub.8 -C.sub.14 carbon chain which may contain one or more inert substituents and each of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 represents a hydrogen atom or an alkyl group which may contain one or more inert substituents and Me represents a divalent metal moiety, wherein:a:b=0.5-1(c+e):b=0.5-0.9d:b=0-0.25(c+e):a=0.8-1.2 andz:b at least 0.1.The compounds can be prepared from a forming solution or gel comprising a source of aluminum, a source of phosphorus, a source of a diamine as defined hereinabove and optionally a source of at least one metal moiety MeO, wherein the appropriate forming components are initially present in specific molar ratios and which mixture is kept at elevated temperature for a period of time sufficient to produce a crystalline aluminophosphate or related compound, followed by separating off the crystalline product obtained and drying, and which may subsequently be calcined.