The equilibrium constant of extraction of lithium, sodium, or potassium picrates, MPi, with 18-crown-6 or dibenzo-18-crown-6 between water and dichloromethane was determined spectrophotometrically and compared with literature values. In all instances, a 1:1:1 complex was extracted. The value of the ionic association constant of the complexed potassium picrate in the organic phase agrees well with that from electrolytic conductivity data. The latter reveals the presence of both cationic and anionic ion triplets in solutions >3 x 10(-3) mol(-1) dm(-3). The effect of temperature on the solubility of dibenzo-18-crown-6 in water saturated with dichloromethane yields Delta H = -16.4 kJ mol(-1) and Delta S = -36.0(2) kJ mol(-1) K-1. Values of the activity coefficient of dibenzo-18-crown-6 at 298.1 K ("salting out effect") in aqueous lithium chloride (0.10 to 0.25 mol dm(-3)) were estimated from the effect of the salt on the solubility, while the activity coefficient of the crown ether in dichloromethane saturated with water was evaluated from the effect of the salt on the partition coefficient. An estimate of the activity coefficient product, y(K+)y(Pi(-)), in the aqueous lithium chloride solutions was made from the effect of this electrolyte on the extraction constant.