Abstract <p>This review considers analytical methods using portable devices combined with smartphones. It covers studies from 2015 to 2024, with an emphasis on recent research. References are given primarily to reviews published in the past 5 years. Devices used in combination with smartphones are discussed, ranging from smartphone holders to portable visible, Raman, and infrared spectrometers, microscopes, and cytometers, as well as amperometric and potentiometric devices and portable microfluidic analyzers. Applications of smartphones to portable devices for immunoassay, polymerase chain reaction, and other nucleotide sequence determinations, to microfluidic devices, and to separation methods are reviewed. Paper-based test systems, photonic crystals, nanozymes, and other specialized approaches—including optoelectrowetting, electrochemiluminescence, hyperspectral imaging, and evanescent wave spectroscopy—are also considered. The main test samples and analytes are summarized.</p>