A Zayre's discount store, a Murphy's Mart and a hardware and home improvement center, Channel Home Center, will set up business in two former Woolco stores in Maryland. The Woolco leases on the two properties, owned by Rosenfeld Realty of Bethesda, were canceled when the F.W. Woolworth Co. closed its failing discount store chain.

Massachusetts-based Zayre Corp. and Channel Home Center have leased the 101,000-square-foot Woolco store at Forestville Plaza Shopping Center in District Heights. Zayre will occupy about 73,000 square feet store and Channel Home will occupy the balance, plus build a 10,000-square-foot addition. Zayre is expected to spend $1.5 million in remodeling costs. The two stores are expected to open in September. The aggregate rental value of the 20-year leases is about $20 million.

Murphy's Mart has leased the 62,000-square-foot Woolco store in Frederick Shopping Center in Frederick. Murphy's Mart expects to open the new store this month. The aggregate rental value of the 20-year lease is about $5 million.

New Jersey-based Channel Home, a division of W.R. Grace & Co.'s retail group, is making its first entry into the Washington area market. Murphy's Mart is a division of the G.C. Murphy Co., which is based in McKeesport, Pa.