Most reliable parameters are derived when the eclipsing binaries show totality in their light curves. The results of the first photometric studies of seven totally eclipsing marginal contact binaries, conducted using data from ground-based observations and the Transiting Exoplanet Survey Satellite mission are presented in this work. All the binaries are found to be short period ( \(\le \) 1 d), low mass ratio ( \(q \sim 0.13\) –0.25), later spectral class (F, G, K), low total mass ( \(\lesssim \) 3.0 M \(_\odot \) ) and totally eclipsing marginal contact binaries. Spectroscopic studies conducted on three marginal contact binaries, using spectra from the Himalayan Chandra Telescope and Large Sky Area Multi-Object Fibre Spectroscopic Telescope, provide evidence of chromospheric magnetic activity. Period variation studies on three marginal contact binaries (MCBs) indicate mass transfer from secondary to primary components. Characteristic studies conducted using various observed and derived parameters for a comprehensive database of 139 MCBs resulted in grouping the binaries into two classes. The classification characterizes them and explains their evolution in two distinct channels following thermal relaxation oscillation/angular momentum loss (TRO/AML).
