A calix[4]arene conjugate bearing salicylyl imine having dibenzyl moiety (L) has been synthesized and characterized, and its ability to recognize three most important essential elements of human system, viz., iron, copper, and zinc, has been addressed by colorimetry and fluorescence techniques. L acts as a sensor for Cu2+ and Fe2+ by exhibiting visual color change and for Zn2+ based on fluorescence spectroscopy. L shows a minimum detection limit of 3.96 +/- 0.42 and 4.51 +/- 0.53 ppm and 45 +/- 4 ppb, respectively, toward Fe2+, Cu2+, and Zn2+. The in situ prepared [ZnL] exhibits phosphate sensing among 14 anions studied with a detection limit of 247 +/- 25 ppb. The complexes of Zn2+, Cu2+, and Fe2+ of L have been synthesized and characterized by different techniques. The crystalline nature of the zinc and copper comlexes and the noncrystalline nature of simple Land its iron complex have been demonstrated by powder XRD. The structures of Cu2+ and Zn2+ complexes have been established by single crystal XRD wherein these were found to be 1:1 monomeric and 2:2 dimeric, respectively, using N2O2 as binding core. The geometries exhibited by the Zn2+ and the Cu2+ complexes were found to be distorted tetrahedral and distorted:I square planar, respectively. The iron complex of L exists in 1:1 stoichiometry as evident from the mass spectrometry and elemental analysis.