Dividends have two (2) specific dates that determine an Investors eligibility to receive them:

1. Last Day To Trade (LDT): Is the last date that anyone can purchase shares in a particular entity in order to qualify to participate in a dividend from that entity. In other words, should you not be holding any positions in an entity by the LDT then you will not qualify for any dividends or entitlements of a corporate action event by that entity.

2. Ex-dividend date (or "ex-date"): Is the date before which your purchase order must be executed in order to receive the dividend. 

For a detailed explanation of the Dividend process from declaration till eventual payment click HERE