The invention relates to benzimidazole-carboxamide 5-HT4 receptor agonist compounds of formula (I) wherein R1 and X are as defined in the specification, or a pharmaceutically acceptable salt or solvate or stereoisomer thereof. The invention also relates to pharmaceutical compositions comprising such compounds, methods of using such compounds to treat diseases associated with 5-HT4 receptor activity, and processes and intermediates useful for preparing such compounds. The invention further relates to crystalline forms of a compound of formula (I).