A dramatic rise in research interest in laser‐induced graphene oxide (GO) reduction and modification requires an overview of the most recent works on this subject. Typical methods for the recognition and confirmation of modified graphene and its derivatives, such as Raman, Fourier‐transform infra‐red (FTIR), X‐ray photoelectron (XP), and ultraviolet‐visible (UV–vis) spectroscopies, are introduced briefly in this review. A major part of the survey is devoted to the main modification ways and the laser parameters used in the literature. A discussion of possible reduction and modification mechanisms is also presented. Recent applications, especially in the biomedical field such as cell therapy treatment, as well as significant results of GO modification, are discussed in detail. Finally, perspectives for the application of laser‐induced GO modifications in passive THz photonics and biomedicine are briefly addressed.

Phenazine dyes and their polymers are reviewed with respect to their application in electrochemical sensors and biosensors, for which they are finding increasing application as redox mediators due to their unique redox and also chromatic properties, being used for the development of (bio)sensors for direct or indirect analyte determination. Electrocatalytic effects decrease the overpotential of a number of important analytes and help increase sensitivity and decrease the detection limit, in some cases, allowing the simultaneous determination of several analytes; their properties as redox mediators can be improved when combined with carbon nanotubes. Future perspectives are indicated.