A two-step strategy for the synthesis of arrays of tricyclic tetrazolo-fused benzodiazepines and benzodiazepinones has been investigated. The protocol uses ortho-N-Boc phenylisocyanides and phenylglyoxaldehydes or ethyl glyoxylate in the 4-component Ugi-Azide reaction to afford MCR (Multi Component Reactions) derived adducts equipped with the desired diversity inputs. A subsequent acidic treatment (TFA/DCE) allows a simultaneous deprotection-cyclization leading to the final products.