Abstract Previous studies have indicated that the δ-carboline (2) ring system derived from the natural product cryptolepine (1) may represent a pharmacophore for anti-infective activity. This paper describes the design and synthesis of a small library of substituted δ- carbolines and the evaluation of the anti-fungal and anti-bacterial activities. An evaluation of the anti-bacterial activity of a previously reported library of ring-opened analogs was also ...