Three sandwich-type neutral unprotonated mixed (phthalocyaninato)(porphyrinato) dysprosium(III) double-decker complexes Dy(Pc)(Por) [Por = TCPP, TPP, TBPP; Pc = unsubstituted phthalocyaninate, TCPP = 5,10,15,20-tetrakis(4-cyanophenyl)porphyrinate, TPP = 5,10,15,20-tetrakis(phenyl)porphyrinate, TBPP = 5,10,15,20-tetrakis[(4-tert-butyl)phenyl]porphyrinate] (1–3) have been designed, prepared, and structurally studied. Systematic and comparative studies reveal the slow relaxation of magnetization under both zero and applied dc field for all three double-deckers, indicating their SMM nature. Stronger quantum tunneling of magnetization (QTM) observed for 3 in comparison with its two counterparts 1 and 2 with similar coordination geometry shows the influence of substituent at the meso-attached phenyl moieties on the magnetic properties.