Porphyrins and other tetrapyrroles are highly suitable for sensing operations based on their synthetic flexibility and chromophore structures where an analyte might interact to stimulate some variation in directly observable optical colour or fluorescence emission modulation. Their chromophore structures also allow access to electronic triplet states, which can be harnessed for the generation of singlet oxygen – a highly reactive species useful for photodynamic action against tumours or microorganisms. Here we discuss the sensing activity of several β-substituted porphyrins1 including not only by the introduction of suitable interacting units but also by the adaptation of non-planar porphyrins for the synthesis of porous structures. The latter are applied for film formation and sensing involving nanomechanical sensors. Selectivity and mechanisms of sensing activity are discussed. We will also introduce new efficient singlet oxygen generating materials based on agglomeration of an oxidized porphyrin chromophore as metal-organic frameworks,2 electron deficient porous polymers, or using resorcinarenes.3 The use of these materials for selective oxidation of organic substrates is demonstrated. Overall, the results demonstrate the efficacy of the chromophore approach to functional materials. The self-assembly properties of porphyrins and nitrogen rich acene compounds, the pyrazinacenes, will also be considered based on contrasting cases of on-surface mobility and immobility, and the introduction of particular functionality influencing the resulting supramolecular structures.