The temperature behavior of the crystal structure as well as dielectric and magnetic properties of the perovskite bismuth chromate ceramics with the 10 mol % Cr3+-to-Sc3+substitution were studied and compared with those of the unmodified compound. Using a high-pressure synthesis, BiCrO3and BiCr0.9Sc0.1O3were obtained as metastable perovskite phases which are monoclinic C2/cwith the √6ap× √2ap× √6apsuperstructure (where apis the primitive perovskite unit-cell parameter) under ambient conditions. At room temperature, the unit cell volume of BiCr0.9Sc0.1O3is ∼1.3% larger than that of BiCrO3. Both perovskites undergo a reversible structural transition into a nonpolar GdFeO3-type phase (orthorhombic Pnma, √2ap× 2ap× √2ap) in the temperature ranges of 410–420 K (BiCrO3) and 470–520 K (BiCr0.9Sc0.1O3) with a relative jump of the primitive perovskite unit cell volume of about −1.6 and −2.0%, respectively. Temperature dependences of the complex dielectric permittivity demonstrate anomalies in the phase transition ranges. The Pnma-to-C2/ccrossover in BiCrO3is accompanied by a decrease in the direct current (dc) conductivity, while in BiCr0.9Sc0.1O3the conductivity increases. The onset of an antiferromagnetic order in BiCr0.9Sc0.1O3is observed at the Néel temperature (TN) of about 85 K as compared with TN= 110 K in BiCrO3. In contrast to BiCrO3, which exhibits a spin reorientation at Tsr∼ 72 K, no such a transition occurs in BiCr0.9Sc0.1O3.