Compound containing a pentalene unit having general formula (I) wherein R1 and R2, equal to or different from each other, are selected from: linear or branched C1-C20, preferably C2-C12, alkyl groups, saturated or unsaturated, optionally containing heteroatoms, cycloalkyl groups optionally substituted, linear or branched C1-C20, preferably C2-C12, alkoxyl groups, saturated or unsaturated, optionally substituted; or the groups R1 and R2 can be optionally bound to each other so as to form, together with the carbon atoms to which they are bound, a cycle or a polycyclic system containing from 3 to 14 carbon atoms, preferably from 4 to 6 carbon atoms, saturated, unsaturated, or aromatic, optionally containing one or more heteroatoms such as, for example, oxygen, sulfur, nitrogen, silicon, phosphorous, selenium; R3 is selected from aryl groups optionally substituted, heteroaryl groups optionally substituted; n is 0 or 1; with the proviso that: when n is 0, X represents a covalent bond and Y represents a sulfur atom (S); when n is 1, X is equal to Y, and represents a CH group, or a nitrogen atom (N). Said compound containing a pentalene unit, as such or after suitable functionalization and polymerization, can be advantageously used in the construction of photovoltaic devices (or solar devices) such as, for example, photovoltaic cells (or solar cells), photovoltaic modules (or solar modules), on both rigid and flexible supports. Said compound containing a pentalene unit can also be advantageously used as a constitutive unit of luminescent solar concentrators (LSCs). Furthermore, said compound containing a pentalene unit can be advantageously used as precursor of monomeric units in the preparation of semiconductor polymers.