An enhanced one-pot synthesis of new functionalized 5,6-dihydro-5,5-dimethyl-2-phenyl-2H-pyridazino[3,4,5-kl]acridin-1(4H)-one derivatives with different substituted patterns by using mesoporous MCM-41 catalyst via a ringopening/ring closure reaction process has been established. This MCM-41 silica catalyst has been synthesized and characterized using an array of sophisticated analytical techniques