The quinoline ring [1] is present in a number of natural [2] and synthetic products often exhibiting interesting pharmacological activities or physical properties. [3,4] Different synthetic approaches for the preparation of quinolines have been reported; the Friedländer reaction (FR) being one of the simplest and most efficient methods. [5] FR is a base-or acid-catalyzed condensation of an aromatic 2-amino-substituted carbonyl compound (aldehyde or ketone) with a carbonyl derivative containing a reactive a-methylene group followed by cyclodehydration (Scheme 1). Generally, the annulation takes place by heating aqueous or ethanolic solutions of the reactants at reflux in the presence of bases or acids, or by heating at temperatures of 150-220 8C in the absence of any catalyst. [6] Numerous studies have been undertaken with the aim of developing new catalysts operating under milder conditions. [5] Concerning green chemistry, replacement of homogeneous catalysts with heterogeneous catalysts for the production of fine chemicals in industrial processes, remains a very active research area. FRs have been catalyzed by several heterogeneous catalysts, such as Al 2 O 3 , [7] H 2 SO 4 /SiO 2 , [8] NaHSO 4 /SiO 2 , [9] HClO 4 / SiO 2 , [10] silica gel-supported phosphomolybdic acid, [11] KAIA[12] and sulfonated cellulose. [13] Although the acid or base-promoted FR has been extensively studied with o-aminoaryl aldehydes, [5] the base-catalyzed reactions starting from the corresponding o-aminoaryl ketones are relatively scarce. In 1967, Fehnel [14] described that o-aminobenzophenone (1 a) failed to react with ethyl acetoacetate under basic classical FR conditions, only affording the 3-acetylquinolin-2-(1H)-one 2 a under thermal activation at 160 8C (Scheme 2).Alongside our recent results concerning the synthesis of quinolines in the presence of bases, [15] we are interested in the development of environmentally friendly and potentially reusable heterogeneous catalysts based on modified molecular sieves with different acid/base properties, and also in the comparison of their catalytic activity in the FR. We have prepared and characterized three different MCM-41 materials supporting aminopropyl (AP), methylaminopropyl (MAP), and diethylaminopropyl (DEAP) groups, and modified the acidic properties of Al-SBA-15 by incorporating cesium ions, [16] and tested all of them in the FR (Table 1) The thermal stability of the aminografted MCM-41 was examined by thermogravimetric (TG) experiments in a temperature range from room temperature to 200 8C. Herein, we report the results of the FR of o-aminoacetophenone (1 b) and o-aminobenzophenone (1 a) with ethyl acetoacetate catalyzed by the mesoporous materials.Initially, we screened for a suitable solvent. Unfortunately, the reaction of 1 b in the presence of 20 wt. % DEAP did not proceed in EtOH at 80 8C. However, when we performed the reaction in DMF or toluene at 100 8C, quinolin-2(1H)-one 2 b was isolated with yields of 36 % and 93 % after 7 h and 2 h, respectively (Scheme 2 and T...