A green and efficient procedure for the synthesis of N,N′-alkylidene bis-amide derivatives has been developed by one-pot condensation of aldehydes and amides in the presence of a magnetic supported acid catalyst NiFe2O4@SiO2-PPA (NFS-PPA) as a highly effective heterogeneous catalyst under solvent-free conditions in refluxing methanol. The magnetically recoverable catalyst was easily recycled at least six times without significant loss of catalytic activity. We report on the modification of a glassy carbon electrode with N,N′-(phenylmethylene)-bis-benzamide (PM-b-B), and how this electrode can serve as a platform for the construction of Ag nanoparticles as a novel electrochemical sensor for glucose detection.