Dimensions of $CR$ are those of
Frequency
Energy
Time period
Current
Dimensions of $CR$ are those of
Capacity $ \times $ Resistance = $\frac{{{\rm{Charge}}}}{{{\rm{Potential}}}} \times \frac{{{\rm{Volt}}}}{{{\rm{amp}}}}$
= $\frac{{{\rm{amp}} \times {\rm{second}} \times {\rm{Volt}}}}{{{\rm{Volt}} \times {\rm{amp}}}} = {\rm{Second}}$
= $\frac{{{\rm{amp}} \times {\rm{second}} \times {\rm{Volt}}}}{{{\rm{Volt}} \times {\rm{amp}}}} = {\rm{Second}}$