Looking to bounce back from an opening-day thrashing at the hands of Coventry, the hosts were again competitive in the first half and should have led at the break.
Isaac Green had cancelled out an early penalty for Darlington with a successful kick of his own, before fly-half Chris Bell opened his try account for the season, Green converting, to give Ionians a 10-3 lead.
With the last play of the half, substitute Simon Uzokwe made an immediate impact for the visitors, his converted try levelled the scores at the break and that would prove critical as Darlington pushed on after the break.
Christopher Auld, Benjamin Frankland and Adam Radwan all went over to give the visitors the bonus point and an unassailable lead. Samuel Wilson scored a late consolation for the hosts four minutes from time, but that was not enough to prevent Ionians falling to back-to-back defeats to start the season.
In National Two North, Sheffield Tigers picked up a 22-18 home victory in the derby clash at home against Sheffield.
The hosts hit the front early, a try from Pete Swatkins and a penalty from Mark Ireland giving Tigers an 8-0 lead, before Fergus Wood reduced the deficit with a try midway through the first period.
On return from injury, Henri Packard went over just before the break for Tigers, Ireland adding the extras, but two penalties from Andrew Hodgson kept Sheffield in touch at 15-11.
Frank Wragg was sent to the sin-bin just before the hour mark for the hosts and the visitors took full advantage, Jonny France going over to put Sheffield ahead for the first time.
However, Tigers scrum-half Ryan Jones touched down with just seven minutes remaining, Ireland again successful with the boot, sending Tigers to their first win of the campaign.
Some strong running from winger Harry Barnard helped Harrogate to a 44-21 win over Sandal in the North Premier league. He scored two tries and had a hand in several others, with Luke Edwards, Charley Purkiss-McEndoo, Andrew Lawson and Noel Minikin also scoring tries.
A 73rd-minute try from Joe Rowntree helped Otley snatch a late 17-14 win at Wharfedale, while Huddersfield lost out 24-3 at home against Hinckley, Joel Hinchcliffe’s early penalty giving them a 3-0 lead which proved to be a false dawn.
Ilkley were 24-15 winners at Morley, with centre Chris Gemmell and wingers Tom Milner and Josh Hall scoring their tries, while Charles Morgan kicked all three conversions and a penalty.
Hull were 30-0 winners at Pocklington, but faced a determined opponent. No 8 Joe Stafford and wingers Steve Hiheta and Mike Adlad scored tries, while they were also given a penalty try.
Cleckheaton battled the elements to claim an impressive 33-7 away victory at Bradford and Bingley in North One East.
The visitors led by just a single point at the break, Mike Haywood going over before Tom Booth reduced the deficit for the hosts.
Cleckheaton pulled away in the second half though, a brace from Cain Crotty and a try apiece from Luke Pearson and Ronan Evans wrapped up the bonus point victory.
West Leeds were 41-26 winners over Huddersfield YMCA.
Full-back Kier Breakwell scored two tries, while wingers Mark Calderwood and Danny Booth added one each, and Dale Breakwell kicked three conversions and five penalties.
Elsewhere, Malton and Norton were 26-15 winners over visitors West Hartlepool and also secured a four-try bonus point, while Driffield beat rivals Bridlington 27-17 but had to settle for just the three tries. And Dinnington lost out 33-3 at Morpeth.