  We analyze the spacetimes admitting a direction for which the relative
electric and magnetic Weyl fields are aligned. We give an invariant
characterization of these metrics and study the properties of its Debever null
vectors. The directions 'observing' aligned electric and magnetic Weyl fields
are obtained for every Petrov type. The results on the no existence of purely
magnetic solutions are extended to the wider class having homothetic electric
and magnetic Weyl fields.
