A palladium(II)/magnesium–lanthanum mixed oxide (Pd(II)/Mg–La) catalyst is a reusable catalyst for cyanation of aromatic C–H bonds by using the combination of NH₄HCO₃ and DMSO as the ‘‘CN’’ source. Moderate to good yields of aromatic nitriles were obtained. An excellent regioselectivity was achieved using the present protocol. A tandem process involving Suzuki coupling followed by a cyanation reaction was also developed using the heterogeneous (Pd(II)/Mg–La) catalyst. This cascade process resulted in the formation of aromatic nitrile from simple 2-halopyridine. The catalyst was recovered by centrifugation and reused for three consecutive cycles with nearly consistent activity and selectivity.