Syntheses of a number of cryptands having heteroditopic as well as heterotritopic receptor sites have been achieved using alkali metal ions as templates. Some of the cryptands can be synthesized on a multi-gram scale without using any templating metal ions at low temperature (278 K). Each of these cryptands readily forms inclusion complexes with transition metal ions. These cryptands exhibit interesting properties and can further accomodate small anions inside the cavity. Further, upon suitable derivatization, some of the cryptands can behave as amphiphiles and form Langmuir-Blodgett films very readily. When derivatized with 9-methylanthracene, some of the cryptands show interesting fluorescence properties and can be of use as molecular photonic devices.

A solution of N, N'-diacylhydrazine ligand in organic solvent is potential for colourimetric detection of F⁻/AcO⁻/PO$^{3−}_4$ via -NH deprotonation, tautomerization and its stabilization as a colour alkali metal complex.

Threaded complexes like pseudorotaxanes, rotaxanes based on Cu(I)/Cu(II) ions have shown to be promising for the construction of mechanically interlocked molecular-level architectures. In this short review, we focus on the synthetic strategies developed to construct pseudorotaxanes and rotaxanes using Cu(I)/Cu(II) ions as template. Further, brief discussions on chemical and mechanical properties associated with some of the selected to Cu(I)/Cu(II) based pseudorotaxanes and rotaxanes are presented.

Tris(2-aminoethyl)amine (TREN) based pentafluorophenyl urea and 4-cyanophenyl thiourea receptors have shown encapsulation of oxalate (C₂O$^{2−}_4$) in semi-aqueous environment. A single crystal X-ray study shows trapping of planar conformer of C₂O$^{2−}_4$ in both the cases. Further solution state binding of C₂O$^{2−}_4$ is probed by ¹H-NMR titration study in semi-aqueous solvent.