Large-scale cubic Pm3n silica monoliths (HOM) were fabricated in wormhole and ordered mesostructures and in shape- and size-controlled cage pores by using a simple and fast strategy. The functional use of these 3D HOM monoliths as probe anchoring templates enabled the efficient designs of optical nanosensors. In this regard, the synthesized chromoionophore was physisorbed into the 3D HOM pore surface carriers without potential leaching. Results revealed that the structural features of the HOM monoliths such as ordered and worm-like cage pores substantially influenced the ion-sensing functionality in terms of their probe inclusion capacities, ion-transport diffusion, optical responsive profile, and visual color transition series during the detection of ultratraces of toxic Pb(II) ions. The nanosensors were selective in discriminating trace Pb(II) ions over multicomponent matrix species, with reliable and reproducible detection and quantification limits. A comparative study on the ion-sensing efficiency of the chromoionophore in both solution and solid phases indicated that the solid HOM monoliths show promise as probe templates to design-made nanosensors for the detection of ultratraces Pb(II) ions. Considering the environmental factors, nanosensors were solvent-free systems and had the capacity to serve as ion preconcentrators with complete reversibility and reusability. The significant features of the probe-design nanosensors led to overcoming the disposal problems, which were normally associated with the liquid probe systems. © 2008 American Chemical Society.