Compounds which inhibit the formation and/or accumulation of RNA foci, such as those due to polynucleotide repeats (e.g., trinucleotide repeats) are described herein. Also described herein are uses of such compounds, such as for the inhibition of the formation and accumulation such RNA foci, as well as for the treatment of polynucleotide repeat disorders (e.g., trinucleotide repeat disorders), such as myotonic dystrophy (e.g., DM1). Such compounds include compounds of formula 1, 1a, 1b, 2, 2a and (3) described herein.