The present study reports the synthesis, structural characterization and myorelaxant activity evaluation of a series of 16 novel 4-naphthylhexahydroquinoline derivatives. The compounds were achieved by one-pot microwave-assisted method via a modified Hantzsch reaction. The structures of the compounds were confirmed by various spectral methods, such as IR, 1D and 2D NMR techniques and mass analysis. X-Ray studies of compound 10 provided further evidence for the proposed structure. To evaluate their myorelaxant activities, the E-max and pD(2) values of the compounds and nifedipine were determined on isolated rabbit gastric fundus smooth muscle strips. The obtained results indicated that the introduction of long chain alkyl groups, such as the 2-methoxyethyl or 2-(methacryloyloxy)ethyl moiety, to the ester group led to the most active compounds.