The term originally applied to compounds having two p-phenylene groups held face to face by –[CH₂]_n– bridges. It now designates compounds having (i) mancude-ring systems, or assemblies of mancude-ring systems, and (ii) atoms and/or saturated or unsaturated chains as alternate components of a large ring. E.g. [2.2](1,4)(1,4)cyclophane [or 1(1,4),4(1,4)-dibenzenacyclohexaphane]. Many chemists include in this class any bridged aromatic system, irrespective of the attachment positions of the bridge.