We report the discovery of two transiting brown dwarfs (BDs), TOI-811b and TOI-852b, from NASAs Transiting Exoplanet Survey Satellite mission. These two transiting BDs have similar masses, but very different radii and ages. Their host stars have similar masses, effective temperatures, and metallicities. The younger and larger transiting BD is TOI-811b at a mass of $M_b = 55.3 pm 3.2{rm M_J}$ and radius of $R_b = 1.35 pm 0.09{rm R_J}$ and it orbits its host star in a period of $P = 25.16551 pm 0.00004$ days. Its age of $93^{+61}_{-29}$ Myr, which we derive from an application of gyrochronology to its host star, is why this BDs radius is relatively large, not heating from its host star since this BD orbits at a longer orbital period than most known transiting BDs. This constraint on the youth of TOI-811b allows us to test substellar mass-radius isochrones where the radius of BDs changes rapidly with age. TOI-852b is a much older (4.0 Gyr from stellar isochrone models of the host star) and smaller transiting BD at a mass of $M_b = 53.7 pm 1.3{rm M_J}$, a radius of $R_b = 0.75 pm 0.03{rm R_J}$, and an orbital period of $P = 4.94561 pm 0.00008$ days. TOI-852b joins the likes of other old transiting BDs that trace out the oldest substellar mass-radius isochrones where contraction of the BDs radius asymptotically slows. Both host stars have a mass of $M_star = 1.32{rm M_odot}pm0.05$ and differ in their radii, $T_{rm eff}$, and [Fe/H] with TOI-811 having $R_star=1.27pm0.09{rm R_odot}$, $T_{rm eff} = 6107 pm 77$K, and $rm [Fe/H] = +0.40 pm 0.09$ and TOI-852 having $R_star=1.71pm0.04{rm R_odot}$, $T_{rm eff} = 5768 pm 84$K, and $rm [Fe/H] = +0.33 pm 0.09$. We take this opportunity to examine how TOI-811b and TOI-852b serve as test points for young and old substellar isochrones, respectively.
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