The present invention relates to compounds of Formula (I), below, (wherein X, R1, R2, R3, p, E, ring A, and ring B are as defined herein). The present invention also relates to compositions (including pharmaceutically acceptable compositions) comprising these compounds, alone and in combination with one or more additional therapeutic agents, and to methods for their use in inhibiting KSP kinesin activity, and for treating cellular proliferative diseases or disorders associated with KSP kinesin activity. Formula I