A microgram-scale X-ray structure analysis of small molecules was developed by applying a modern high-throughput crystallization technique to classical co-crystallization via acid-base salt formation. The use of an automatic dispensing machine for the crystallization screening reduces the required amount of sample to the microgram scale. Absolute configurations of a chiral alkaloid and three chiral pharmaceutical acids were obtained by X-ray crystallography from 210-530 mu g of samples by this renovated method.