The kinetics of complexation of Li+ and Na+ in the low donor number solvent nitromethane with the cyclic polyether dibenzo-24-crown-8 (DB24C8), dibenzo-18-crown-6 (DB18C6), and the acyclic polyether tetraglyme have been investigated by ultrasonic relaxation techniques. The work was done in the frequency range 1-600 MHz and at 35-degrees-C for the Li+ systems and at 25-degrees-C for the Na+ system (except for DB24C8 because of low solubility of the ligand which necessitated working at 35-degrees-C). Working in excess Li+ with the ligand size mismatched, ligands DB24C8 and DB18C6 give some evidence of multimetal cation intervention in the complexation affecting the reverse rate constants. Use of the open polyether tetraglyme with Li+ and Na+ permits the observation of two relaxation phenomena in the microsecond-to-nanosecond time range covered by the instrumentation. Evidence of anion interference in the complexation mechanism at concentrations larger than approximately 0.1 M is also found, a result that is predictable from the low donor number of nitromethane.