The design and study of hybrid crystalline solids in the search for multifunctional materials is one of the most appealing possibilities where molecule-based materials offer striking advantages: from the combination of molecular building blocks with the desired tailor-made chemical and physical properties. In this review we will cover all aspects of the so-called molecular ferromagnetic conductors, built from combination in a single compound of organic cationic radicals, able to give rise to conducting architectures, with polymeric anionic metal complexes, able to give rise to ferromagnetism. The relevant successes and drawbacks of this approach will be highlighted and discussed in detail.