Compounds of formula (I) are disclosedCompounds of formula (I) are useful in treating conditions and disorders prevented by or ameliorated by PDE10A ligands. Radiolabeled compounds of formula (I) are also useful as diagnostic tools as PDE10A positron emission tomography ligands. Also disclosed are pharmaceutical compositions comprising compound of formula (I), methods for using such compounds and compositions, and a process for preparing compounds within the scope of formula (I).