Recent advances in the design and synthesis of five-membered heterocycles containing both sulfur and selenium atoms—1,3-thiaselenolane and 1,3-thiaselenole derivatives—are discussed in this review. These heterocyclic systems are of interest as intermediates for organic synthesis and compounds that can exhibit various useful properties, including biological activity and electrical conductivity. The main focus of the review is on the works of the last 20 years that make use of catalytic reactions. Synthetic methods for the preparation of structurally related 1,4,5,8-diselenadithiafulvalenes based on catalytic cross-coupling reactions are also presented. To date, the design and synthesis of 1,3-thiaselenolane and 1,3-thiaselenole derivatives have not been discussed in a separate review.